I've got a GAT right hand stock also.
I love this stock, it fits me great, but I had to modify it a little.
My hands are long and thin, so the palm swell needed more beef to it.
So if you are worried about the grip being too small, I bet it is samll enough.
A little bondo, some saran wrap, and tada, a custom fit grip. Just have to rought the stock up a little first to get it to stick.