I've used 2 1/2" binding on Minky backed quilts ( I always include batting) but, I prefer thin binding on my quilts. If you like a wider binding you certainly could use 3". Are you applying it with a wider than 1/4" seam? If so that would make a wider one easier to deal with. I always used the standard 1/4" application so did not need my binding to be wider. ( I actually generally use 2 1/4" wide strips but do add that extra 1/4" when using flannel, batting, Minky combination. )