A spindle with less runout will certainly help with the fuzzies but
it’s only part of the equation. I’d measure the runout on your
current spindle so you can compare with others.
Here’s some other suggestions that’ll help eliminate them:
Make sure your stepover isn’t too large for your cutter size.
Some people run a second pass, I don’t find it necessary just to get
rid of fuzzies. Sometimes, I’ll run a second at 90 degrees to the
first if I want a perfectly smooth surface.
Make sure you’re using a good cutter, I had a few once that had
terrible runout themselves.
Green wax has the most plastic and produces the toughest fuzzies, go
ahead and give it a try if you’d like, but purple should be fine.
Use lube; a water based cutting fluid helps reduce them, I use a
drip system, some people use a few drops of mineral or soy oil on
the wax before cutting.
Give that master blaster a try again, I use a similar gun and it’ll
give me perfectly clean waxes.
These topics have all been covered in depth at 3dcadjewelry.com if
you need more info or pics.