Great work! I hope to see you develop it in the future.
I'm sure you'll find the best way for you and how you like to go about it. This is just an idea. I've always been a fan of this persons fat suits.
https://www.youtube.com/user/Nikki19NY/videos
She says she uses shapewear and garbage bags filled with water. I thought it was particularly clever.
I've always been so-so on fat suits. But I like the work and creativity that goes into them.