I don't have a sandblaster, so any etching I do of boro is done in my tumbler. I have three dedicated barrels, one for 600 grit, one for 1000 grit, and one that isn't used for etching, but is used with stainless steel shot for polishing my metalwork. Yes, only need one grit. Indentations do not get etched and stay glossy, but this can be used in your design. The first article I wrote for GlassLine was about some techniques you can use on your beads to take them further and tumble etching was one. I LOVE the feel of tumble etched glass!!
Clear boro tumbled etched