I like that upmarket lens cleaning brush Dave and the de-luxe sensor cleaner hanging near it, with that snazzy lens cleaning cloth on the right. As you say, edge falloff of light not bad atall atall. You could of course stick a single sheet thickness of tissue paper down the middle third of the gun's diffuser to even up a bit - meaning one third clear, centre third with tissue and the third third clear. Couple of test shots with one and two thicknesses would show which worked best.
