I can't help you with a source. However, I will just say that I've had a bathroom where I installed 2" tiles and another where I had 1" tiles, and I ended up regretting both due to the many grout lines and how they got stained in places over time. In my latest bathroom remodel I went with 2' X 2' tiles and am loving the minimal grout lines. I'm not trying to discourage you...just pointing out something in case you hadn't considered it.

Thanks! my original plan was to choose a 12x24 tile for that reason, but I ultimately really love hex tile and feel bigger format tile won’t be authentic to the era of our house. While I’m not going for a replica look, I want the hard finishes to feel as though they could be original. I’m planning to use a medium gray, stain-resistant grout.

I thought you might be going for traditional, which was why I first hesitated to comment. I think the stain resistant grout will help a lot.