Of course you are trimming a V shaped cut that allows the oil trapped behind the gasket to fall back into the motor. And you are using a fish scale to get just the same pull on both bolts. And of course you removed the studs and chamfered the tapped holes and checked the engine surface with a flat file.
I obtained some 'rubber' gaskets from RGM in Cumbria, UK - I say rubber although I'm sure they must be neoprene or some type of silicon compund - suffice to say I have no oil leaks since fitting them - they are also re-useable. I seem to recall they cost about £7.00 for the set of three - take a look in their catalogue or email them.
Hey Cash, I had a set of covers that were doing just that, leaking thru the cover. The way I fixed it was to get the inside of the covers super clean and then use high temp paint on the inside, Works great. This was after thinking it was the gaskets and going half crazy trying to get them to seal. Good luck, Chuck.