I was confused with why a 2.5 inch binding wouldn't work til you said minky. I would use a walking foot to attach that one. Minky is so slippy. Good luck!! With regular fabric I always press I like the crisp but do whatever is easrier and works for you. I would do 3.5 for a minky because I always do 1/2 seams with minky and trim. Just me!