Have your tile setter make you a sample board with YOUR tile and several grout colors. A good tile setter will do this for you. If you are supplying the material you may need to pay him however.

I did black grout on my bathroom floor big mistake it now looks much lighter than the tile I wanted to match so I would do the lighter gtrout if I was to do it again

Thank you Patricia. I was worried about that. He did a sample board of the PB Charcoal and it looks like black.