heatshield problems

I drank the kool aide and got a heatshield for my HD shotgun today for no other reason than I think they look cool. My problem is that it binds my forend up and makes cycling a feat of superhuman strength. Im not afraid of modifying anything, I just want to know whether I should take material off of the heatshield or the forearm...or both?

I already filed a few thousandths off the forend but any more is going to require a dremel (which I dont have) since filing is a slow process.

suggestions?