Thanks Lowell. I'm thinking the butt stock is too long for the setup though. I may need to find me a plain old cheap M4 stock.
Took quite a bit of nibbling away at the back of the stock and grip to get it to feel right in the hand and look decent with the adapter. Don't have the tools I used to so it's a bit rougher than I would like to see, but at least it tells me those stocks are salvageable if desired.