Yes sometimes the front gasket is a real bear. Make sure that the metal piece is not warped from over tightening; they bend a lot easier than they look, perhaps because the piece has five holes in it. I tried to fix one once and could not get it to stop leaking then I finally looked closely at the end piece and could see about 1/8 of inch warp!!!. Anyways Indian head gasket sealer works well there also because you can put it on the screws and the shims at the same time. I heard a guy once suggest using a thin bead of silicone on each shim and bolt also, and I think that should work too.
Steve