You also might want to post this on the Home Decorating forum. Usually lots of good help with paint colors over there. Also, I think if you could photo your samples on something more neutral than the granite it would be helpful. That bold granite is going to skew perceptions, I think.

link: Home Decorating

Here are a couple of popular BM greys with your finishes.

Thanks for posting those pictures, they provide a good visual. The stonington gray looks interesting. I also came across Nimbus which appears to be a lighter gray. Based on the photos I have been searching, the shade of gray paint versus tile/stone does not appear to be a concern.

Will check out the other forum as well.

Happily we relied on our designer to pick our white bathroom's grey wall color - BM Aura Whisper.

Whisper works well too.

Thanks for all the suggestions. I tried a sample of the Nimbus today which looks promising. Planning to use Mapei warm grey grout, which would be a little more grey tone.