Drying motors are not useless, but they aren't essential, either. You can turn them by hand and get fantastic results, but you have to babysit them for a few hours. Just turn them 180 degrees when you start to see a sag on one side. A drying rig is useful to have and does give nice results as well. I've done both ways, and time usually dictates that I use a dryer most of the time.
30 RPM is just the output of the motor. You can use an o-ring or a gear to reduce the RPM to wherever you want it. I have some older versions of that motor, and it is all metal and has served me well so far. I didn't know they cheapened it in the meantime.