Don, I glue the valve cover gasket down with 3M trim cement (AKA Gorilla Snot on the NASCAR circuit). It makes a convenient dam for the oil that drips off the rocker arms. No sealer on top- - - -which allows the valve cover to be removed easily for adjustment checks. I stopped checking when the dial indicator made a full revolution- - - - -100 thousandths. I'm going to guess probably 1/8" or so with the Elgin E-323 cam that's in that engine.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!