What would be the best way to modify my incog to accept g26 with RMR?

I sent off my g26 slide to be milled for an RM08g.I mocked it up on the slide and it seems like I will need to take a little bit of material off the top of the incog for the gun to seat properly.Obviously I won't do anything until I get the actual setup back.I don't have much experience modifying holsters. I'm thinking there won't be much material to take off at all. Do you think a hand file would work or will it shred and peel off the "tactical fuzz"? Would a dremel be a better choice? via /r/CCW http://ift.tt/23ECgl0