There are a lot of variables why these settings might not be ideal for you but I have had pretty good luck with 950 / 100 at 340 LPI. I have been thinking about backing off the power a little on the next run. Yes, I put a light coating of dish soap over any part of the surface that will get engraved. To date, I think I have sold about four shot glasses. Will take a while to pay for my Glowforge at that rate but it’s a start.