Not sure why anyone is telling you the ports dont need to match they surely do need to match. If they dont it will unbalance the engine at high rpm and it will make less power. One bad port can drag along and slow the engines total rpm loosing a thousand rpm can mean 100 hp.
If you use a shop vac to suck the chips down the port andout the valve side you can kinda see how the air flows incents or a cigg can give you a smoke trail to follow. Stright line of smoke means good flow stalling or circling air is poor flow. But way to much to explain in this little box.
Also keeps iron dust from causeing damage around the shop. Forgot to mention this but dont port near your painted cars the rusting chips will screw up your paint. Also not good for lungs and any other things you can think of.
Less is more just cut the casting marks smooth and flat and stick the heads on the car. Also try to do all the ports at once one cut per port makes them easier to match up and prevents you from spending 20 hours on the first port and needing another 120 hours of work to complete.