I would say 1/2 inch holes on the bottom is to big. On one of my bins I cut a rectagle out and put screen but on my plastic bin I didnt put any holes. You get a feel for how much water is right and dont saturate it to bad. As far as air I move my soil once in a while and it seems to work fine. If you look on that web link he has a bin that could be made easy, you see PVC threw the bin. I dont have anything like that and my worms are doing fine.
