I kinda half assed drilling mine. Used a metal bit, bore the hole, and then cursed myself as I had to grind down the shavings. Mine was a SS pot though, aluminum is a bit softer if I recall.
What you really need is a step-drill bit, like this:
I thought it pricey to get it for two holes though.
Ball valve wise, I just used a bronze ball valve. Everything I've read says the only harm from bronze comes from letting it be in contact with the wort over long periods (days), otherwise it's no different that SS. Some might debate that, but to each their own. Same with hose barbs etc. Got it all from Northeast Equipment in Saint John.
Theres a place in saint john that high temp o-rings too, and they were the perfect size to create 1/2 inch weldless bulkheads. I have the receipt tucked in wallet still, otherwise I'd forget what it was. Keep meaning to put it somewhere safer, but haven't. Think the whole setup for the valve cost me about 25 per valve. Pics are somewhere here from when I made them I believe.
