How do you determine deck clearance in an engine using math?

If you are running alloy heads with flat tops on the street;

some of the guys on FABO are running a tic over 220psi on pumpgas, with a tight squish/quench.
I myself have run up to 195psi, still on 87E10.

The point is, that to get that high pressure you will need to coordinate with the ICA of the cam; and if you start with an Scr of only 9.5, then you could quickly end up with a doggy engine pushing 130psi. I guarantee that 130psi will be a big disappointment.
Once I tasted 195 plus psi, I know I'll never go back to even 160psi.
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BTW
my KB 107s dropped in at .012 below the deck on my 1971 block. I decked it to zero, and I ran that with an 028 gasket. But at the end of the season, on teardown, I found that gasket had migrated nearly into the valley.
I cut the decks again for a pop-up of .007, and used the FelPro 039s.
Three years later, my little 223* cam dropped lobes.
So I installed the next bigger cam, (230) and I advanced that cam, in an effort to get more pressure. But it was no use.
I got me a transmission with a lower first gear, and retimed the cam to straight up. Pressure is now around 185, which is NOTHING like 195! But, the top-end rush sortof makes up for it.

Of course if you cannot afford alloy heads, you are sortof stuck down at 165psi max on best pumpgas.
Whereas at up to 195, I was still on 87E10.
At that time my car was a DD, and I estimated that those alloy heads had payed for themselves in about two summers, just in the difference of the cost of the 87E10 versus 91 gas, alone. Not even allowing for the difference in fuel economy, which I have no way of comparing.

Some guys on FABO poo-poo high pressure, which I don't understand. I'm never going back to Iron heads @155, which barely supports 87E10.