Twenty-five bucks and he never paid for a cut again? That clipper has to be running on pure spite at this point to survive that many haircuts. I'd mess up the back of my head so bad the first time that I'd be paying double to get it fixed.

Wait, so the grout color wasn't the problem at all, it was the ratio the whole time? That makes me wonder how many people rip out a perfectly good backsplash when all they needed was to tweak the mix a little. I did something kind of like this with a bathroom wall where I kept adding white to lighten a color and it just went chalky and flat, and what actually saved it was adding a tiny bit of the original dark back in to give it some life. It sounds like your 70/30 thing works because the light accent keeps the darker base from going muddy, which is the opposite of what most of us do when a color looks off. Next time I pick a color I'm going to grab two samples up front and play with the ratio instead of trusting the little paint chip.