Here is how I did mine:
First thing to do is find a plate of thick aluminum 7/16 would be ideal.
1. Take the motor off of your Grizzly and take the alluminum drive pulley off the motor.
2. Transfer the motor's top bolts (3 of them as you will see) on a sheet of paper and drill and tap the alluminum plate to bolt the plate directly on top of the motor. You must also drill out a center for the shaft to go through the plate as well. ( I did this all with a handheld drill given my lack of drill press)
3. Mount the plate on the motor. You will need to get longer motor bolts from hardware store, then place the drive wheel on to do a test fit. Check for square between the plate and drive wheel and shim accordingly under the plate (I used a couple washers between the plate and motor). You will notice the drive wheel has a slight crowned center, but is flat for the lower 2.5 inches...I simply made all of my jigs to be high enough for the material to contact that flat spot, and thus did not turn the drive wheel flat.
4. Make a guide ring to fit between the plate and the drive wheel and bolt that to the plate.
5. Your in business.
It takes some time and effort, but you can do it for under $100. That being said, crooked stiks method is ideal and professional.