Here is the first trial run for a small order I have taken. I am reasonably happy with the result.
Afeuro 5w laser
Dollar store highball glass
Spray on galvanized coating (water and sponger cleanup)
Multiple passes to account for different focal needs.
100% power
4 passes
900 mm/m
.1 mm line interval
Coffee, not whiskey for photo 
Good job, but…
I think galvanize has zinc in it. You should use white or black acrylic paint instead. I use an EXPO Dry Erase Bold Black marker with good success.
With the spray galvanized, I can run a 15% power run to lightly etch a trial position and not leave a mark on the glass. I will get a dry erase marker for the future.
Prototype going well, down to 3 passes with better focus discipline. The first pass to burns the coating black, then the next two break the surface of the glass. Still learning 
The fine details were a problem. The final run was a lot longer than I had hoped for, almost 2 hours for each tumbler.
#1. Burned the zinc coating black
1500mm/m
1 pass
.1 spacing
crosshatch
1 pass
900 mm/m
100%
.1 spacing
#3 second etch
Cross hatch reverse order
1 pass
900mm/m
.08 spacing
#4. OFFSET fill
.08 spacing
100%
900 mm/m
