Why not have a chubbyish BBW board, and a bigger BBW board? All the girls on BBWR are huge, never get dat flabby but not too huge look I'm going for!
This is an interesting twist, usually the request is for an SSBBW board. With traffic the way it is, I'm not sure if creating a board specifically for chubby women will have the result that you want. I could see it if /BBW/ were somehow inundated with OC that needed to be split, but for right now the OC is pretty minimal as it is. As for now, I'd recommend starting a chubby thread in /BBW/ if there isn't one already.
this is bbwchan. if you're not here for fat, you're probably in the wrong place.