but it was Grace's first day. I had planned on only doing half a day's worth... and going half speed for at least a couple of units. However, it went so well, that we did a full day's work!
Granted we are not doing DITHOR yet, and I'm not going to go through Story Time with her this year... I'm reading Preparing and then CTC's story time to all of them in the evening. I figure we'll catch Grace up on Bigger's story time when Julianna goes through it in a couple of years
I also didn't do dictation today, but she started that last week... so she's "ahead" already in that, and I have decided that I will do R&S completely orally for the first third of the book. So we did the entire left side, plus R&S, math and science in less than an hour! I'm so proud of her for listening. I believe she's going to excel using Bigger
She was also very nervous about "starting 3rd grade work" and was excited to learn that she completed everything I had planned for today and tomorrow.
It sounds like you have a good plan in place too. 
The things that Jayden would balk at in Bigger and take FOREVER to do (science notebooking for instance) literally took Grace 10 minutes, and that included getting everything she needed out, finding the Bible verse, and doing the work. And her drawing was VERY VERY clear!