Well, I've finally joined the late 20th century and gotten a digital camera. I've had really good experience with my flow through bins and wanted to share them with you. I'm single and live in a 20th floor studio apartment, so I couldn't do the big outside garbage can with wheels. I got 2 tall kitchen trash cans (about 9 months apart.) I got whatever was at Walmart, there's no other rhyme or reason to the color/shape choice.
A friend took out a 'window' and I drilled holes. To create the 'bottom' of one, I used the kind of wire you use to hang up paintings just because that's what I had. For the other I used a thicker insulated copper wire because that's what the hardware store was selling as a remnant. I didn't even realize there was copper in there when I bought it. To secure the wire, I tied the ends around a bit of wooden chopstick.
I put a couple of pieces of newspaper lining the bottom (being sure to have it go up the edges a few inches), and added a small amount of mostly finished VC (an inch or two). Then I put in the contents of a half composted rubbermaid bin, food and more moist shredded newspaper.
For the white one, I only put 2 layers of newspaper down and clearly that wasn't enough. I put moist newspaper bedding down to keep escapees alive until I could get to them. For the tan one I used 4 layers of newspaper and that was more than sufficient.
When I made the second (white) one, I used that opportunity to re-do the older one and put the wires 1 1/2" apart instead of 1". Here a knot was sufficient to secure the ends. There's no problem with potential escapees here because I made sure the newspaper went up the side of the bin. The first time I built this one, the newspaper went just to the edges and I had lots of explorers dropping down and not being able to get back up.
In the past when I've harvested I've just used my hands (since I can put the bins up on a table and don't have to get on hands and knees). Some of the newspaper lining the bottom goes back in the bin for the first harvest. It takes a day or two but everything sinks back down to the wires and stays there. There's a little extra that falls through after the harvest, but that only lasts 2 or 3 days. From then on it's pretty solid. Mine gets really really dry to the point that I add water weekly to have some moisture so I don't kill off all the bacteria.
My experience is consistent with Jason's. I add food and more bedding and come back a week later and the level of the contents are where they were before I added the previous feeding. I'm sure it slowly goes up, but it's not very noticeable. Part of the reason Is that I make sure there's lots of air pockets in my newspaper bedding. As that gets eaten it shrinks. I've got less than a pound of worms in each, so it's not the amazing eating machine that Jason's new flow through is, but it suits my needs perfectly.
I hope I've inspired some small time indoor vermicoomposters to make a flow through next time they need to split their bins!