A big part of whether or not your child is ready for Bigger has to do with the volume of writing. There is a weekly history notebooking page, a weekly notebooking science page, they write up a science experiment each week, and then there is vocabulary each week that the child would complete. Also, you mentioned that you would not be completing R&S. Was there another program you were planning to use? R&S is used mostly orally (2/3 oral, 1/3 written) and I know that some families have used it 100% orally for Bigger. My two youngest have used it this year and it has been a great year. I also was using AAR level 3 for my middle child when I started Bigger and I had no trouble with that. I finished using AAS by Christmas and switched over to the literature selections in HOD and my middle child is now completing so much reading on his own along with completing DITHOR.
HOD is very different from other programs when combining kids. I am not sure what you did before or if you combine before but with HOD, it works best and smoothest when kids are placed in a level that they can complete all of the activities listed in the guide. When I first started HOD, I started last year and used the levels Preparing and Beyond. For me, I combine my youngest (who was 5) and my middle child (who was 7) at the time in that guide. My youngest is extremely advanced and figured that she could do the same level as my son and wasn't worried about the age range. Honestly, for that year, it was great. I had no trouble at all with her doing anything in Beyond. However, the volume of work significantly increased the following year! In Bigger, there was quite a bit more writing activities scheduled. And then I knew that by the time she got to Preparing, it would be even more writing with adding on quite a bit of independent reading. So at the end of last year (when we finished Beyond), I decided I did not want to continue on that path as it would lead to my youngest to Preparing when she is 7 years old. The topics would continue to get more mature in nature as the years go on and the workload volume would just continue to increase each year. I decided to split her and my son up for this year. I actually bumped her down to Little Hearts and modified it to look more like Beyond. This was the best thing I could have done and am so glad I decided to do it!
I say all this to encourage you. I think if your 7 year old doesn't really place in Bigger, then you are going to have to drag him through and modify stuff every year. One thing about HOD is that each level, when completed as is, is structured to preparing kids for the following level. In Preparing, they are actually preparing children to become more independent. They start reading 1/2 of their history to themselves and all of their science to themselves. By CTC, they are reading all of their history and science to themselves. If children are bumped up too early and not ready for that level of independence, mom's workload and teacher time dramatically increases. It doesn't just increase for that year, every year will end up being the same result. HOD isn't set up to ever repeat a level. So you will just have to keep pulling that child through every year and helping them more and more. By high school, that child will start WG in the 8th grade and the length of the school day increases even more. With HOD, each level is set up to have a certain amount of teacher time and a certain amount of learning time. As long as kiddos are place properly in their levels, then you are doing the correct amount of teaching having them do the correct amount independent time which will make your day go very smoothly. However, if you are having to hold your child's hand significantly and your child isn't properly placed, this will make HOD seem like it is overwhelming and you will probably quite using it.
For what it is worth, if it were me, I would try and split some stuff up for your 7 and 9 year old children. I would place the 7 year old in Beyond. And I would then place the 9 year old in Bigger. I would however combine a few boxes. I would combine the poetry, Bible and storytime boxes. This will save you a lot of time and significantly soften the blow of running that extra level. Reading, math and language arts would have been completed separately anyway. So the only thing you are splitting up is History, the rotating box (it includes science in Beyond) and have the oldest complete the science box in Bigger. For poetry, Bible and Storytime, I would specifically follow the Beyond plans. This way, when your 9 year old moves up to Preparing and your 7 year old moves up to Bigger, you aren't "repeating" anything to the 7 year old. Also, these boxes are extremely similar in nature. For handwriting, I would have the 9 year old do cursive with Bigger and then have the 7 year old do the handwriting in the guide. So the only real increased volume in your day by completing both Bigger and Beyond would be the time it takes to add the History box for Beyond and then to complete the rotating box. You are looking at adding a max of 30 minutes (probably closer to 20) depending on the length of those two activities.
So your day would look this for those two kids:
Reading about history (own guide - teacher led):
15 min - 7 year old;
20 min - 9 year old
Rotating Box (own guide - teacher led):
10 min - 7 year old;
15-30 min - 9 year old (the 9 year old will eventually be able to do some of this independently)
Poetry (combine in Beyond - teacher led):
5 min - both kids at the same time
Bible Study (combine in Beyond - teacher led):
5-10 min - both kids at the same time (this includes the music CD and both kids could listen to this alone without if you wanted them to)
Storytime (combine in Beyond - teacher led):
20 min - both kids at the same time
Science (only Bigger - teacher led):
20 min - 9 year old only (your 9 year old will move to being able to do some of this stuff themselves)
Handwriting:
Copy poem - printing (7 year old): 5 min (complete independently)
Cursive (9 year old): 5-10 min (complete independently)
Language Arts (own program)
Reading (own program)
Math (own program)
One thing I did want to mention is I see that you use mentioned you will be using BJ and Daily grams next year for your oldest. Are you entirely against using the LA from HOD? When I first found HOD last year I had my own set up going too. But I decided that my LA was a lot more work and didn't mesh as well. So when I started HOD, I decided to use their selections for writing, grammar and DITHOR for literature. It made my day very balanced I do actually really like their programs. At the time, I was using All About Spelling with my kids too. But then there came a point when my oldest out grew the need for it. This year, I switched her over to dictation in the guide. It was a fantastic move. My dd's spelling has been improving ever since. I also decided to try Singapore with my oldest this year and am glad I did that too. I am not necessarily recommending the switch with the older kids - I would never recommend jumping around in math. But for the 7 year old, if you aren't incredibly happy with your math program, I would consider it. I switched my middle child and youngest child over to Singapore as well at some point during this year because my other program (Right Start math - which I do think is a fantastic program) was just becoming too teacher intensive for me. My younger 2 kids are pretty good at math and they have switched to Singapore and are flying through it. They love it. Their lessons are much shorter and I like the challenge Singapore provides to them. I like that they just have to "think" about some things to answer the questions.
You will probably notice my theme where I keep talking about "balance." Balance is one of the beauties of using HOD but really is only attained when you use as many of their products as possible (or at least keep your own products time wise in line with their time allotment for that subject). Their program is set up with kids and mom in mind. Their program is set up to meet the needs of the children and they are probably the top most program I have ever seen that covers a significant volume of important skills all while pair them up with your main subjects. For example, I wouldn't use a heavy reading program like BJ for your oldest because there is already a lot of reading in CTC. DITHOR is the literature portion of HOD's program and it is very balanced with the volume of reading your child will be doing already in their year. I also wouldn't do daily grams if it were me. There are 180 lessons. That is a lot! HOD is set up to be completed 4 days a week for 35 weeks. In CTC, grammar is only scheduled twice a week. And then writing is scheduled twice a week. By using your plans, you are going to have a lot more lessons, teacher time and work for your 11 year old than what HOD schedules. That makes for a longer day and it may then seem like there is just too much work. R&S is truly a wonderful program - plus it is scheduled to be completed as 2/3 oral with 1/3 written making grammar take only 10 minutes each day that it is scheduled. If it were me, I would give next year a try without anything different, especially for your oldest. Now, the beginning of the year may seem odd and you may want to jump right back to your old programs. I just want to encourage you to give it one full year with HOD only (except math). At the end of the year, if you hate it, then switch back. Daily grams is a ton of review so even if you decide that you didn't like R&S, you wouldn't have really lost any ground. The same with writing, if you feel like you hated it, you can decided for yourself next year what you want to do. I also want to see if you would be willing to try dictation. It seems very odd to me that it does teach spelling. But I promise you, it works! Another major benefit of dictation is that it also teaches grammar
That is why I love it! So I am not sure what you are using, but I would pray about switching and giving it a full year. I have found that when I made some of these major changes, it was not the smoothest transition in the world at the time. But after a while (a few weeks or even a month) it got exponentially better. Even the writing program in CTC had to grow on me a bit this year. But man o man do I love it now. Part of my problem was that I was expecting a bit much from my dd at the beginning of the year. I have since put my expectations in check and my dd is completing some beautifully created prose that have increased in descriptiveness as the year goes on. I can see this writing program feeding into my dd's approach to her written narrations as well. It has been a fantastic fit and I love the skills my dd is gaining.
So, I wrote a lot. What your thoughts?