Just a little suggestion and perhaps the mods can fix this, but it's always good to keep "similar" threads together. This thread on tile choice should really be in your build thread so that people following your build could chime in. Having multiple threads related to a single build can get confusing. It's no big deal or offense or anything, just good posting practice.
Not sure about the tile choice. I suppose the grout is either going to be white or grey. I hate grout line but some don't mind them. If it were me, I'd try the bigger tile first. Just work out a deal with your PB that if you don't like it and want it chipped out for smaller tile that he isn't going to charge you an arm and a leg.