You certainly can use the “leftover” part of the butt…I’ve made coppa before and honestly…only one of the 2 butchers I bought from knew what I was even talking about..maybe purists would poo-poo it being an authentic coppa..screw them I say. I’m sure you could get similar results with a port tenderloin but same thing about the purists. I’m not a foodsaver expert..the one thing I do know about them is I’d never buy another (chamber vac snob here and the killer of at least 5 foodsavers). The wet function I believe is their attempt to accommodate a non-chamber-vac’s inability to deal with liquid in the bags. I don’t know if you have access to a real butcher shop..but the one I go to would almost certainly run your projects thru their chamber vac…assuming you are buying product from them. My country butcher will do a lot of things for me. I did a bone-in beef ribber and when it was done and trimmed, they ran it thru their meat saw for me.
My $.02 worth.