Head gasket thickness

So started mocking up and checking clearances. Noticed my domed piston are .024 out of the hole. Not sure if I am accurately figuring out my gasket thickness. So my question is if the piston is .024 out of the hole would I just add ,keeping the ideal .040 quench just add .040 to the .024 and start from there? Then maybe I can start checking piston to valve clearance. Any useful help is appreciated.
What are You working on, and what kind of heads, is it a closed chamber with the quench/squish area flat at the gasket/deck surface? If the pistons were at -0- deck & the
heads are as the example I chose, then add .024", You'd pretty much have to come up with a gasket .060-.065" compressed. It would be better to have the pistons topped in
that instance, to remove the .024", but not cheaper!!