I've done a couple with the Grainger motor and you just need a coupler like is on the turnback crank, to attach to the motor. After that, its a simple matter of building a bracket to attach the motor to, directly beneath the variator. After you have the bracket in place, you need to get an appropriate length driveshaft from one of the original parts suppliers, if you don't have one lying around. Invariably its going to be too long, so you'll have to cut it down to the desired length and weld it together, making sure its straight. Its really pretty easy if you have any mechanical skills at all.
Keep trying with Joe. I haven't talked with him in a while but he's a little hard to get ahold of.