[NSFW] Trying to figure out expanding models in SFM

So I’m trying to make some hyper sfm content to upload here, but I’m trying to increase the rear size of the femmepyro model. I’ve seen art where people have increased it to a massive size. What I did was bake procedural bones and added a scale to the lbutt and rbutt, but the thighs don’t increase with it, so it looks very strange. Anyone know how I could maybe fix it so the thighs scale with the butt?

hey so I know this question is more than old but their is a modal that’s somewhat good that can at least get you a good starting point

this guy is the one who kinda kicked off these kinds of sfm modals
https://www.tumbex.com/donandark.tumblr/posts?page=1&tag=expansion