OK everyone I thought I would show a picture of my vertical flow through bin. The top right picture shows the bottom of the bin where castings are harvested. Since Red Wigglers like to stay in the top 2-4 inches of the bin very few worms if any are harvested. This also has the advantage of not disturbing the worms during the process of harvesting castings. I will try to explain more about this type of bin and others when time allows.
Vertical flow through wormbins are the most efficient method of raising worms or producing vermicompost. The largest producers of vermicompost use these very same bins! Albeit, on a much larger scale, automated hoppers for adding more material, automated watering, as well as a bar pulled on a winch that automates harvesting as well. The bin above is capable of holding 10-15lbs of worms if it is well cared for. I believe I had about 30 dollars into the project and a few hours of time.