I got the stock and adapter from Blackjack, it is same one as the one on RSA site just little less $. Works fine with the scope, but with irons I have to tilt my head over the stock to get the whole thing to line up. This wouldn't be too bad on x39,but is somewhat painful with .308. It only needs to be about 1/2" lower.
Saw a similar stock set up in the TAPCO catalog and it seems to be a little lower. I could also get the "no tang" block and AR adapter from ACE. Or a whole different stock. Not a big deal. Got other things to worry about-my '03 SAR-1 developed trigger slap from sitting around.