compression or flow?

I’m kinda running into a compression vs flow deal right now. My buddy wanted 2.08 valves in his Edelbrock heads but his also going to run a 4.040 Cometic head gasket. Well like I said before the Speedmaster heads have a nicer chamber than the Edelbrock heads. With that small gasket I’m not even sure I can work the chamber enough to make his 2.08 valves pay off. I try to size everything close to the 4.180 felpro gasket size.