what’s a good rear bag for the R3M?

I want to buy a rear bag more suitable to the Edgun’s stock. I’m using a Harris-clone bipod, and want a stable rear bag to use for my informal bench-rest shooting. I’m thinking a long-ear’ed rear bag that will allow me to pinch the ears to hold the rear stock steady. Anyone got any brands, types, models in mind for me to check out? Protektor comes to mind.
thank you,
Darryl