piston dome size need help

[Stefano]

You are going about your quest Bass Ackwards.

You need to first determine what you expect to get out of your engine, which is based on many factors such as how you plan to use it and get out of it? RPM range? HP and TQ level? etc?

The only working parameter which you provided is "pump gas".

Once you have determined the above you can decide on a combination that will best achieve your objective.