I was frustrated and concerned that the 3/4" pin in the MINI wasn't really deep enough to put in the MICRO and have it even with the surface. I'd even like it to be a little below the surface, because some of these seedlings so close to the top are floppy, and I want to give them a little extra soil for support. I had Tim add a small piece of something to the insert to give it a little more depth. At first it didn't work real well--it may have been too deep. He made tweaked it a bit and now it's working well.
I also went back to the "drawing board", in this case the pottingblocks.com website, to review the procedure. I think my mixture wasn't wet enough at first. I made it wetter, and it's working great now. When I drop the blocks from the device, I'm also pushing down and up a bit as I release them, to remove the suction before I allow it to go all the way to the bottom to drop.
All said and done, the MINI blocks, with MICROS planted in them look like this:For "bottom" watering, I'm using these cake pans with lids. (I know, I bought these things, but at least they're cheap, and re-usable.) I drilled some holes in the bottom of the aluminum pan and place the plastic lid underneath. I can lift the aluminum pan out, pour water into the plastic lid, replace the aluminum pan with the blocks, and the water soaks up from the bottom to water the blocks. Nice.