honestly what comes to mind would be, instead of completely hacking off the inner part of the reflector as a whole, instead cut the same section off, BUT only on the outer face of the lens, leaving the frame of the whole reflector, of course also gutted to fit the light in from behind, then graft a flat clear plexi lens for the part of the reflector lens that was removed, sealed to the surrounding frame that was left in the first step, then all it may need is to be tinted a bit, or blackout edged, something along those lines, wouldn't be too difficult really & would look flush with no gaps or anything...