That's what I was thinking. Half full of media is going to be well over the 3 lb limit on that tumbler. I don't expect to have all my ingredients till next week. I'll have to use the old trial and error method till I get it figured out as to how much media works best.
While I think I'll want to cast my own lead balls at some point in time, for now I'll just wait and see if the molds eventually become available again. Surely at some point they will.