I agree, the factory RMR plate isn't that great.There are some significant gaps in the fore/aft of the plate for the optic and the plate isn't super snug. The screws are tapered so I think that will create some better surface area to "squish" the plate down and they sit just flush with the top of the plate so the optic also holds it in place (along with the threadlocker and torque). I'm going to run it as is for a bit and see how it goes but I'd like to see a plate that is more snug and offers front and rear support to the optic.
I ordered a Milspec plate from C&H for the Holosun 509T, hopefully that one fits more snugly. At least it looks like it supports the optic better than the factory RMR plate I've got.