Hi FT, I can understand your concern about the D-loop getting twisted, however having been there and done it with swivel head Chappy boss release aids, I see no difference in performance or groups with a fixed head release aid to be honest. I use a Carter Just B Cuz now and find it very comfortable. It can chew up D-loops a little, but even so the d-loop will last a season out and I get the bow string replaced once a year any how.

IMHO I would not wory about string twist, more importantly buy a release aid that feels comfortable in your hand. A release aid will not torque the string on a compound unless it has a realy high let off. I guess your bow will be the normal 65%, it will be fine.