Its how much horsepower and torque the engine actually makes and how well that engine accelerates up thru the power curve that counts. Not the flow bench numbers. You will be removing about 10cc of metal from each port.
The limit on how big you can open up the push rod pinch is the push rod hole. Nice to not bust thru there either.
The minimum intake port cross sectional area size. (the smallest area of the port) pretty much detemines the rpm where peak HP is created. You can have 240+cfm flow at high lift, but of the MCSA is too small the port "chokes" ( air goes supersonic in the port) and chokes off the top end power.
Thats why just working the first inch and last inch of the stock port leaves a lot on the table. its hard to make these ports too big. but its far too easy to over work the port entrance.. Unless you are using a big full race single plane race manifold, felpro 1205 gasket size is plenty big. Its just right for the Performer RPM and Vic Jr on a street motor.
The two point you got to watch for when porting is the push rod pinch wall and the common wall where the cylinder head bolt hole is. this is where you are likely to make a hole. Use common good sense here.