I have a few snappers left and have thought about taking them out of the snap case and putting them in an amaray case. What is considered the best type of amaray case to hold a snapper's cover w/out tearing the plastic? Should I cut some of the cardboard sleeve for this to work as well?

You're not going to fit them into any amaray case without cutting or bending the original cardboard. Honestly, just forget that course of action entirely and just go to one of the many fine custom cover sites and download/print a size-converted snapper scan. It'll look a million times better. Email me if you need links.