106 Days Question

Its nearly August and I still havent nailed down science.  I am so undecided and need some experienced momma advice. My kids are 8, 11, and 13. In the past I have done family science with my oldest having additional independent readings on the subject. I purchased Elements by Ellen McHenry for him to do on his own, along with Mystery of the Periodic Table. After looking at the curriculum I think it would be sooooo much more fun to do together. Lots of activities, games, etc. But my younger two may not be terribly interested in Chemistry, aside from experiments. So I thought 106 days might be better for them. But it looks like the Considering Gods Creation assignments might be great for my 8th Grader. Now I dont know how to fit in two family sciences. And with my oldest close to high school I want to give him more independent work. So I guess my question is whether 106 days with Considerign Gods Creation would be enough for an 8th grader. I would add in additional reading and written narrations on whatever subject was being studied. The Chemistry curriculum could easily be done in one term or expanded. Then do 106 days term 2 and 3. Or should I do 106 days with only the youngers and leave my 8th grader on his own. All my kids will no doubt make a stop at a JC before college so traditional science is not a concern for me, a love of Gods world and solid creation science is my goal, the ability to stand firm in an evolution pushing world. I know that is a lot of background, sorry if I am too wordy. So here are my options

a) 8th grader on his own with chemistry, 6th and 3rd grader together with 106 days

b) family together term 1 chemistry, term 2 and 3 106 days (extra reading for 8th grader)

c) family together chemistry and 106 days all year

Any suggestions? Better ideas? I am torn between family together and everyone telling me my kids should be more independent. Any help os appreciated.

thanks!