Cabelas has a LaCrosse AlphaBurley that seems to be made for them to sell exclusively that has a zipper down the entire inside as well as the slit & strap on the outside. The calve section is quite comfortably snug when it's zipped up, but if nothing else works for you, leaving it unzipped or partially zipped would give a LOT of calve room. It's a top of the line LaCrosse boot, NOT a Cabelas brand; so it's not low quality. I have them and they're a dream to get on and off, and zipped up are very well fitted.