I haven’t tried it yet, but I plan to do exactly the same project in the near future (customized whisky bottle). The bottle I’m customizing is too big and round for the GF so my plan is to use the laser to cut a stencil and then attach the stencil to the bottle and sandblast it.
The simplest and cheapest version of this concept would be to cut a stencil out of some adhesive paper masking material and use a chemical glass etching cream. You can buy the cream on Amazon or at most craft stores.
The bigger problem is that you can’t get too detailed in a stencil you plan to transfer to a bottle. Small text or intricate patterns are going to have small pieces of stencil that will need to be transferred and placed very accurately. You can not cut them out completely, and finish it on the bottle with a razor, but really small details might still produce unsatisfactory results.
Also, I personally I think sandblasting gives better results than chemical etching, but it requires more tools and a sturdier stencil (usually vinyl, but that’s a no-go in a laser, and the alternatives are pricey).