I have the same one at work, you can get the two speed 3/4hp with a cast iron stand and wheels/polish/rake for $1k shipped from TP tools. The long arbors are the best part, you just can't get the right angles with how close the wheels are to the motor with bench grinders.

You can either switch wheels or clean the old compound off with a rake and then apply new. The latter is obviously removing material from the wheel though so if you are switching often it's probably worth getting another wheel. Switching is easy and I keep a handful of different sisal and stitch wheels around for different compounds. Here is how I have it now with a Scotch-brite light deburring wheel, which is really good for a pre-polish or removing tool marks.

Pro tip: Keep your compound in the fridge until applying, it melts slower and more of it gets pulled into the wheel instead of being sprayed all over the wall/ceiling/your face.

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