Ok, I made a brass cam button and now I need to see if my numbers and assumptions are ok.
Superformance gasket thickness .051
total gap between cover and camshaft using clay with no gasket and bolts tight .648
cam button length .684

assumption 1: Roller cam end play .005-.010
assumption 2: Gasket crush .005-.010

So I get for math
gasket .051
minus crush -.005
plus gap +.648
equals =.694
minus button -.684
equals gap =.010

If I crush .010 on the gasket, my endplay would then be .005

Is my math ok? Are my tolerances ok? Did I miss anything?

I'm not sure you can crush those gaskets that much. Your idea is correct, just not sure what the endplay is that you'll end up with. I'd recommend using a dial indicator to check the end play.

I will when I get it together but wanted to get the button close. I have some .006 shims that I can put behind the button. Thanks for the response. Tim

I have an end plate with a window in it so I can quickly check the end play. I include these window plates with the timing covers that I sell.

I have measured the crush of my stamped steel timing chain cover and water pump Felpro gaskets (0.031" if I remember correctly) was like 0.001" FWIW

Your math looks right to me.

But....
I agree with Andy you likely won't crush the gasket that much.
And I don't think you are going to get a clay reading within plus or minus 0.005"

Third, depending on the timing cover stiffness, that will help you determine the desired end play. i.e. a stock timing cover will flex a bunch, so you don't need much end play. A cast aluminum cover won't flex much, so you need a couple thousandths more.

there is a .045 4130 chromoly plate welded inside the stock cover which is shaped like the original V recess. I just hope that I can shimm up any extra with my .006 shims....

Andy, your cover is wonderful and excellent quality, just beyond my price range for this engine. Hopefully I can get one on my next hemi! Tim