Grout colour for border mosaic

[SK 1]

I’m tiling a bathroom with a cement grey tile and mosaic glass border. I’ve tried a couple of different grout colours but the grout I like for the tile (mid grey) seems too dark on the mosaic.

Would it be crazy to use a different (lighter) colour grout for the border. And if it’s not a ridiculous idea, any thoughts about how I should go about it? Mask the border?

Thoughts appreciated.

 

[White Room]

You can but it can be a pain, dark grout first and when dry use a grout protector, then use the lighter grout but keep the area your grouting to just the border not plastered all over...good luck

 

[Spare Tool]

Small pieces of window seal strip pushed into where the joints cross work better than masking it, as above do dark first..