You'll probably find in a bigger cage the fleece stays fresher because there is more room for the pigs to move around. I'd give it a trial with the fleece and see what you think. If not then you could change over to disposable.
As he/she is a skinny pig, I would recommend fleece or vetbed. Skinnies don't have much fur so their skin is more prone to being scratched etc., which means you'll want to use the softest bedding as is possible. I believe fleece is fine in pretty much any size cage, and if you don't want to do any sewing and your piggies are fleece burrowers that's fine. What you can do, is make sure you use a sheet of fleece that's big enough to overhang the sides of the cage (not the grids, I mean the corrugated plastic) so the sides can go under the grids. The grids would hold the fleece down to make it burrow-proof. Or you could tuck the sides underneath the cage.
