Hey all, here's how I use rapid rooters. I take a 4 penny nail and make a new hole beside the center hole. It fits the stem of the cutting tightly and more securely than the center hole and that's how they work best. You can't push the nail straight down or you'll come out the side and you don't want to go all the way through the bottom of the rapid rooter either.
Unless you're trying to root really thin cuts, it's usually pretty easy to push the stem down into the new hole. Then I rack em up in ice cube trays, alternating holes to give them some space (or maybe four to a tray if they are large cuts) and I keep a little water in the bottom of the trays to keep the rapid rooters moist. I put all these in a clear sterlite tub from big lots with plastic wrap to cover most of the top to trap the humidity.
In summer I have a ghetto ass cloning chamber that is made from a big TV box, styrofoam for insulation, a lexan top and a dorm fridge with the door removed on one end for cooling. I just put the trays directly in there with the lights on top and outside to control the heat. It's shit to look at but it was cheap as hell and it works!