This machine does the trick however a few things i have learned...

It takes about an hour to polish a rock (depending on hardness of course). i spent about 6 hours on the first one trying to figure it all out

I bought a 260 diamond wheel. To go from 180 to 325 grit was too big a jump and i could never get the scratches out. the 260 saves A LOT of time

Once you go past the 325 grit you aren't getting anymore scratches out. the 600 seems like a wasted disc to me. would be nice to have 180, 260, 325, 1200, 14,000 paste and i think that is the ticket

I tried running at lower RPMs but i see no difference, just crank it up to 6.

Its hard not to push down, i try to only apply gentle pressure and it seems to work good.

very important to wash the pads and the rocks all the time to keep debris off or you will never get a good polish. I have been doing 3 or 4 rocks on one grit, then clean everything, move to next grit and grinding the 4, cleaning everything, etc etc

I store all the discs in freezer bags when not in use to keep debris off

3" and under work best for rock size. You can do 4" or elongated ones but it gets tight with that center knob. Would be nice if they could figure out how to secure from below with a quick disconnect or something so you get the full 8" work space

hope this helps, i have been getting good results now with this process