I signed up for the Reddit Secret Santa and made a set of coasters out of slate from Amazon. I used the settings that others have used and posted in the spreadsheet.
I used some cardboard to make a corner template, cut the cardboard using the same outline position, and then ignored the outline cut. Then I placed the slate and ran the engraving. 2.5 hours and they turned out really well. I bought the designs on Etsy.
No idea if the recipient likes them; they haven’t even posted they have received the package yet.