I've built a couple of them using 2" pipe (which is actually quite a bit bigger than 2"). They work well, but seem to run a little hot, especially when it's windy. I put a 1/2" wide baffle in mine which seem to get it under control. Charcoal usage is the same as a Weber lid. You want to have a way to cap it off, because if you close the intake and exhaust, your fire will (or should) go out quickly, which will save you some charcoal for the next cook.
I'm very intelligent, but I mask it by doing stupid stuff.