Hi: Is the size of the nylon overshell larger if 100% overfill is ordered (as compared to the regular fill shell)? I require a roomy fit boot/shoe/slipper. I usually buy size 13 slippers or 12 XW if available. My concern is that if the shell of the 100% overfill socks is the same as those without overfill, that they will feel too tight for me. I would prefer the overfill socks, but what would you recommend? Might I have a problem with even the size 13 regular fill socks? I have pairs of footwear stored in a closet because I cannot wear them..........I would not want to add these.