I only keep the smaller cats, under two pounds. If you cut through the skin behind the "ears" all the way around, then nail (clamp) the head, and with a good pair of CeeTee's, you can pull the skin all the way down to the tail.
Filleting from that point is fairly easy. But I prefer to wrap them in foil and toss 'em on the campfire. If it ain't messy, it ain't eatin'!
Hope this helps.
Harold F.