External Balanced 360 With new parts still Balanced??

I had this concern about building my 360 so what I did was done a bunch of research until I found a piston that weighed pretty much the same as my factory ones. I found that a speed pro h116cp. 03 over was within a couple grams of my factory pistons. @nm9stheham helped me out with it he did some research and testing of his own with the weight in the pins to get the piston the desired weight (factory weight) that way the balance doesnt change. Afterwards I talked to my machinist and he said for a street car thats not gonna be turning a consistent high rpm a few grams wouldnt hurt. I cant remember which way it was over or under but the factory balance was not perfectly balanced anyway and going over in weight would get you closer to a true balance. Going under weight like a kb107 pistons (they are considerably lighter) is where you start running into balance issues. I have no experience other than what I have read and talked to people so I cant say for certain that is true. I have talked to both types of guys one says rebalancing is mandatory in every build and others say they have never rebalanced one. I was talking to a mopar guy I work with that swears he built a 360 with kb107s and was spraying it with the factory rods and crank no rebalancing and it was running 10s in a 68 barracuda. Once again idk how much truth is behind that. My block is in the machine shop now i am not having the crank balanced I will let you know if I have any trouble with it.