I don't think you're going to laser martini glasses. The laser requires the surface to be parallel to the table and the angle on the glass is so steep, it's not going to work. You might rig up something to do one or a couple, but for 3,000, sand carving is the only way to go, in my opinion. Plus, you'll have a superior result. Lasering glass creates small, tiny fractures in the glass to make the look. Sand carving removes the material.
Heck, you can even buy the masks already made and sandblast them yourself.
I'd never think about lasering a 3,000 piece glass job, even if they were straight glasses.
I suppose you could chemical etch them too. You still need to buy the masks already made.