You've got to be a bit cautious when using sanded grout with glass due to the possibility of scratching. Some glass scratches and some don't. Test grouting over a sample glass tile before you commit fully so you aren't surprised on your installed tiles. On that point, Laticrete's Permacolor would probably fit your needs very well because the sand used in the formula is smaller and more rounded in shape than typical sanded grouts...so it's less likely to scratch. And unlike other sanded grouts, it has a range from 1/16" to 1/2" width grout lines.
When I need to use a cementitious grout, Permacolor is my first choice...especially because the final dried grout matches the sample colors...no surprises on color variations. Take a look at Laticrete's "Toasted Almond" color...might be a good color for you?
Tonto Goldstein….. but my friends call me Bubba
"The best way to get a bad law repealed is to enforce it strictly"
- Guy on the five