Just to clarify this. Your snake responds to 3 things, heat, scent and movement... which is why we tend to recommend people not make SFEs (Stupid Feeding Errors).
A hand that smells like rodents, moves like a rodent, and is emitting heat will get tagged as well as a rodent.
Hence using tongs, pre-scenting, and not handling when you smell like a rodent.
When my snakes are in feed mode I do not put my hands in the enclosure ever.
To the OP, I think the paper plate idea is a great one. One other thing you can do is ensure the prey is dry (blowdrying it) and removing your water dish.
I remove my water dishes when I begin my pre-scenting and put them back in once the snake heads into their hides following. This way it will not drag the prey through the dish, and then through the substrate.
Bruce