Heya Rando
Hmmm haven't actually seen the rig you are talking about but sounds weird to me. The gang could live happily with a popper but a slice would would either be acting as a sinker or fishing at speed it would just end up in a big mess.
If I had to guess I would say a quick change sinker would go on the snap. A large sinker would keep the gang off the bottom but pull the popper sub surface which no longer makes it a popper in my opinion, while a light sinker might allow the popper some action on top while keeping the bait just below the surface. Mix and match to see what depth the fish are working?
I'd be interested in hearing from someone that has used them sucessfully myself, can see some possibilities but am only guessing on how they are supposed to be used.