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

Bewy said

You really need to confirm the deck height if you want an accurate number. Not easy to do unless you have the mesauring equipment.

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Oh, I agree. That will be done. I was just curious about the method that I'd heard people use to get the approximate deck clearance numbers.
The last 2 engines that I built, I had the decks milled to get the deck height where I wanted to get the compression ratio to the target numbers.
Ever try to build a 383 with some decent compression? I found that the short stroke really makes it difficult unless you use domed pistons. Even with the pistons a mere .009 in the hole, I was still only able to get it to 9.2 to 1 with iron heads that also had been milled.