Valve Clearance on Larger Camshaft and Flat Top Pistons

To your questions, assuming you have had to cut the reliefs deeper to get clearance. Would you need to have a piston with a pop up to regain compression? No, go thinner head gasket. Cometic makes an .029 gasket with other thicker options before you get to .050. That being said a pop up can help with quench.
Thanks. My thinking with not relying on the head gasket to increase static compression if I lose some with cutting deeper reliefs was that I'd be battling myself to a degree, in that I'm cutting reliefs deeper and losing some of that cut by bringing the valves back down closer to those reliefs with a thinner gasket. There's going to be more cc change in the head gasket change than the relief change, however, so I could find the sweet spot where the additional relief to account for the valves and thinner gasket will net me the static compression I had before the relief and gasket change.