The bigger the better in most cases. I have a UDS that I made. The charcoal basket is about 15" diameter and 12" deep. Starting with a heaping basket I only get about 15 hours of 225-250 temps out of it. I wish I could get more because the last time I did butts they barely made it at 15 hours and the smoker was dying down. I just foiled them and put them in the cooler to let the residual heat get the centers. The one pulled a little tougher than the other so I know it could have used a little more time in the heat.
This is so very true, expanded steel is an unforgiving b**ch! I have a nice 3" cut on my shin from where the basket grabbed my shoelace and decided to bite my leg. Nothing serious, just about knocked me on my ass though.
Burnt Fingers, try to get expanded stainless if you can. It'll burn much cleaner so you don't really have to worry about breaking it in. My local metal shop had that galvanized crap which is coated in zinc, after some searching the guy found a nice piece of stainless 3/4" that was about 4 'x 3' and only cost me $30. Also wipe it down good with some acetone/ nail polish remover to get rid of the oil and rinse with water.