What i would do is bolt the heads on just as they are with a fresh valve job. Then after you run the engine awhile and you really know how it runs pull the heads and go with your plan. This will show you if what you did made a difference or not. You can flow bench and port heads till the cows come home and untill you can verify the changes you have made work it just a waste of time. You may actually be suprised that the engine runs better with the un-ported heads!!!!!
Just my .02 Keith