Welcome to the HOD Board!
It is nice to meet you! We did CTC last year, and I'm sure your oldest will love it. We also did Beyond and half-speed LHTH last year. I see your dc are similar in the age spans as my dc. Each of my dc are 3-4 years apart, with very different abilities. For me it has honestly just been easier to do separate guides. I know that is not the case for everyone, but it may be worth considering. My teaching time for CTC was around an hour to an hour and a half, so if your oldest is fairly independent and if you are using the LA and Math HOD suggests or using different LA and math that still fits in the time allotments, your teaching time should be similar to mine, and your child's time is probably around a total of 4 hours or 4 1/2 hours.
Beyond... takes about 2 1/2 hours to do, so that is quite doable. I am wondering if you did all of the history, science, and storytime readings from LHFHG last year? I can totally understand having to spend some key time on reading skills with your ds, I was just thinking that the history, science, storytime readings from LHFHG were what really helped my ds be able to listen better to the longer readings in Beyond. If you didn't do those, you may want to go back to LHFHG and do the left side along with the storytime, but then add in the right side LA and math from Beyond. I know you sold it and I truly can empathize with that, but it would be worth getting again to have ds placed well in those areas. The kind of listening ability you are describing in regard to your ds definitely fit the listening ability of my dc when they did LHFHG, so I am thinking that may really help him out to do LHFHG for those subject areas.
It would take a pretty advanced 5 yo to do Beyond Little Hearts. I almost would never suggest that, as it sets that little one up to always be on the too young side for the skills expected within the guides. When you look at the placement chart, where would your 5 yo fit? I am thinking it would be wise to either do LHTH with her, or to do LHFHG with the 8 yo.
Whatever you choose to do, I think that the biggest thing you could do for your ds is to just read through the readings without stopping. CM believed that you should not stop in the middle of readings to clarify, to explain further, or even to define an unknown word. This was a tough idea for me to embrace, but over the years I have found it is a very good rule of thumb to follow. I've noticed my dc lose the flow of the reading when I stop, and they are also frustrated by my "drawing it out" for them. Just reading the material straight through and then clipping along with the follow-up really helped them begin to listen and comprehend better. CM was a big fan of the "short lesson", and I was unfortunately sometimes a fan of turning the short lesson into a long lesson.
You may totally not be doing that, but in case you may be at times, I thought I'd share how much changing that one little thing has done for my dc's attention span and attitude. Knowing the alloted time increments was helpful for me too, so in case you may find that beneficial, here are a few links:
Beyond, time it takes:
viewtopic.php?f=6&t=4390&p=32417
CTC time it takes:
viewtopic.php?f=6&t=3765
The short lesson idea was also helpful in teaching our dc to read. I set the timer, and after 15 minutes, we stopped. As they grew older, the time lengthened out to 20 minutes or a tad more, but after that we stopped. Your ds may appreciate knowing if he gives you his best attention for 15-20 minutes, he will get to be done with that until the next day. Is the phonics program you are using going well for him overall? If not, sometimes just changing to a different program can do wonders, as there are many excellent phonics programs out there, and some click better than others with different dc. I hope something here helps, but prayer is always the best deciding factor! So, I will pray for you as consider proper placement, and I will also try to help you however possible as you consider ideas for your dc.
In Christ,
Julie