Take one of your RC rims to Home Depot and find the ABS that fit's as snug as possible. Have them cut you a couple of feet and then just cut the ABS to the width of your rim and you should be good to go. If it is a little loose, wrap a layer of electrical tape around the rim and then put the ABS on and glue it. Always make sure you glue the ABS otherwise it will just come off of your rim and you'll ruin your rims. The sushi's a less of a hassle because they're pre cut and the edges are beveled not square. To me it's worth it to just buy the Sushi's.

Good luck!