Oh wow, I wrote that some time ago.
Should have posted an update, but I did switch over to the .. I think it's called the UF20. It's the slightly taller version of the two reactors by Vertex that people seem to be using for pellets. With the same pump, but now using 1/2" lines instead of 3/8", the difference in tumbling is quite significant. I haven't had to touch that thing in a number of months and the pellets are still spinning away in there.
I'll see if there's something I can snap a photo of, or maybe someone else can do so as well ... but in the meantime, imagine an acrylic disk for the bottom plate, with a grid of holes about 1/8" diameter or so. If you've seen the bottom plate of a TLF Phosban150 reactor, it's more or less the same idea.