Cam / Compression Ratio
Because you are on pump gas I would pick the compression ratio first. Why? Because you are limited by the fuel you can get at the pump. Maybe you only want to use 87 octane pump gas, or just run it on mid grade.
Whatever you decide that’s what you have to live with. If you pick the cam first, you then have to use a camshaft that meets that one criteria first, and then the cam needed may not run your power brakes or maybe it needs a looser converter or more gear than you want.
In fact, I almost always pick the cam last, after I have the compression ratio, head flow, tire diameter, gear ratio, shift rpm, trap rpm (if you are going to drag race it some) and highest cruise rpm you’ll see. Then you can make the best decision on cam timing, rather than picking cam timing first and making that dictate everything else.
I understand cam selection is sexy and exciting but that one choice will have more influence of how the engine behaves than any other single component.