Valve seat stones sizes?

You need 2.125 or 2.25 x 45* at least. Just get the seats to clean up, no more, for 2.02 valves. Then top dress them with a 15* stone to get the seat to the right diameter. Then bottom dress with a 70*, or 60* stone to narrow the seat to what you want. The pilot should be vertical, so gravity has no influence on the cut. Make sure the stone holder has almost no play on the pilot. Sioux is a very good seat grinder. Use a vernier caliper when grinding valves, the fine dust will not throw them off. Check seat by lapping one valve to verify diameter and width. I dress the stones after 4 seats.