After looking at the placement chart, I'm confused, again

My son could fit between Bigger/Preparing, but now I'm leaning more toward Bigger than before. We tried to do this guide a couple years back, but I got cold feet and didn't follow through.

Long story, I'm sure Julie/Carrie remember.
My ds is past phonics, needs some spelling work with rules (Friday, he spelled "running" - "runing) so need that. He hasn't completely mastered cursive. Handwriting has been a little difficult. He still wants to print everything with large letters. However, he has worked well with Cheeful Cursive and is still working through that book. He can write a paragraph with encouragement

. He is behind in math, but making progress. He'd rather be doing anything besides school.

However, I manage to get most subjects done daily, with textbooks. O.k. sorry this is so long! DS is really only lacking in the handwriting area. However, not sure if he'd be ready for extensive writing/narrations that might be in Preparing???
My question is, if we use Bigger, would we need to use the extension package? I do already have some of the books in that package. Not sure??? Just looking for advice/placement help once again!

Thanks for your kind words and help! You all are great on this board!
momofone