Look into Norton's 3X wheels. 80 or 120 grit will do the job. The bummer is that you have a 6" grinder, which in my opinion is too small to do a good job on turning tools. The disadvantage to a 6" wheel is that it creates too much hollow grind on the tool, which can cause issues. Hard to rub the bevel when the bevel has a very distinct curvature. An 8" grinder would be a good investment, and an even better investment is a good slow speed sharpening system like a Tormek with a 10" wheel. I use an 8" and it works fine. My 6" grinder only gets used for lawnmower blade sharpening!
As far as Minwax....That's a brand name but they have dozens and dozens of different finishing products. What are you finishing, what is it being used for, what is the desired finish look, etc.?