You just need to size the beds to the amount of nutrients you have. The answer though is that you need less space for worms than for fish. You also need a lot less support for them. A 30 gallon rubbermaid tube can hold 15 pund of worms, and they can eat about 10 pounds of waste a week. BSF's can eat 10 times as much and produce much more "tea".

Anyway, this is the early stages. We just need to give it a try. The numbers look very good to me though.