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.