Yes, you heard right. By flipping the motor backwards. What happens the the motor hits the compression and flips back, causing the motor to turn counter-clockwise and start.

Your test stand will work, but you need to anchor it down. The motor is going to pull very hard and you don't want it coming loose when you are anywhere near it.

1/8" is not too much to trim off of a spinner. Just make sure you trim the same amount from both sides so that it stays in balance (more or less).

So much money? Wait until you hit 5 figures. It doesn't take long.

Hope this helps