External or internal balance?

I am in the process of building my new 408 stroker engine. Just got the block back from the machine shop and I know it is .030 over so now it is time to order the rotating assy. The question is to have it balanced or not. Since I am building from scratch, I can go either way, but I just dropped the transmission off at the shop and should tell them if the flywheel/torque converter should be weighted or not. Is internal balanced or external balanced better in general, or does it really matter, assuming you get the right combo with the rotating assy chosen.

So, I understand that if I go with a balanced rotating assy, I need a zero weighted torque converter/flywheel and harmonic balancer. If it is not balanced, I need a counterweighted converter/flywheel and harmonic balancer. Just want to make the right choice. This will be an engine rated at appx 500 hp/500 ft/lbs torque, if that matters.

Thanks,

Brian