I had to trim my laminated gaskets the same way to make them fit better with the stamped steel valve covers (mine are the repros). Once I got the good fit I did the RTV on the one side and let them sit overnight flat on the workbench with a little weight on top. Next day I ran a small bead around the inside lip to make sure it was all good, then installed on the head. Nice thing was that I did not have to work it as two items and have the gasket slip out with the RTV mess. I also found that the Orings were not that good of a fit so I took a tube and cover into a place that sells O-rings. Dude was a car guy so he was into helping me find a better fit. #318 is snug on the tube and a firm fit into the valve cover - Zero leaks for the past 5 years or so.