I can tell you from personal experience that both are great to a experienced knifemaker. Personally I would probably prefer Poly if it were just me in the knifeshop.
But recently a 5" poly wheel I found had really grooved up corners and sides of the poly. I found a in-experienced friend had...
Man that looks nice. I like how you left the bandsaw teeth. Lets people know what it was in its former life. Plus you could use it to cut something harder that you did not want to use your scallops on.
CW
I just checked out the links Josh linked. It appears all the diagrams show the AC power going to the Red master on/off switch.
And the motor wires (Blue and brown I am guessing) go to the Fwd/Rev switch.
Goodluck
CW
Wait and get the carbide edge one, Buy once.
I use mine to scribe all kinds of stuff. I just scribed the bottom of a kydex holster yesterday that needed 3/4 cut off of it for a shorter barreled gun.
I mostly use it to scribe two lines on the edge before grinding though.
The reason I say get the...
I usually used Half glass beads and half aluminum oxide as my favorite go to Bead blast formula. I forget right now the grit size but can get back to you.
CW