David,you should be ok. I'd hold out for a 68". What #are you looking for?
I dunno. I think 66 inches in a mild R/d is too short for a 31 inch draw. Yes, the bow will handle it, but it will stack, and you will feel finger pinch. 68 would be better, and 70 inches better yet, though few folks make a mild rd in a 70 inch length. Good luck in your search.Edit added: Wasn't that familiar with the Super D so checked his website. The Super D is an ASL, not a mild r/d. Definitely go with the longer bow in an ASL.