By the sound of it you personally are installing said floor... ever done it before? At least do a practice run and DO decide on the optimal length of the boards. It’s essential to the process to plan ahead and have a VERY good mitre saw. I jumped in to the deep and and I did my first floor ever in HB. Needles to say it did involve taking a crowbar to a few duds before getting it right. ...And know the centre of your room. I decided on a “carpet” of HB with straight run planks bordering the perimeter. But do listen to SW... doing it all in this method will be overkill, especially in what appears to be a very small apartment or house based on the floor plan. And which way do your joists run? Never lay flooring parallel to a joist unless you’ve added an extra layer of ply as an additional subfloor (its code my friend). So lay the floor across the joist as much as possible. AND get a moisture meter. If the floor is not properly acclimated you will have “shrinkage”. Not a good thing.

try a 4x16, 5x15, 5x18, 4x20, size tile. these will give you 1 1/2- 2 V's. remove your baseboard. when you get to the closet, just follow the design layout and take the pattern into the closet (that way you won't have any cuts showing under the door) just for a visual, these are prob 4x16 bring home a box of that size and lay it out to see if you like the size. you could go up to a 6x18, but I wouldn't do any larger, otherwise it looks like this. and if you like this, then do this size and turn the tiles in this direction.

for a small powder room, it is recommended to use smaller wall tiles. but it really is completely up to your style preference.

Thanks Beverly. Yes, that was my initial thought too...as I mentioned in my original post, the hallway is what's throwing me off. I had first settled on 6x24 exactly for the reasons you posted (I also have some of those exact pics in my inspiration folder!). I thought the herringbone had to at least show for a full W in the hallway...but then got hung up about the 6x24 size throughout the rest of the floor. For the bigger expanses, I think 6x24 is too small, and one of the tile contractors gave his opinion that the V look is "better" (considering all the factors of the larger foyer/kitchen footprint) down the hallway. That's when I went up to the 6x36 and 8x40 samples. Here's what it looks like in the smaller 6x24 as you're suggesting (don't pay attn to the color of the tiles...I'm going for a whitish with hints of gray) ...BUT don't you agree that 6x24 will look pretty bad for the larger floors? Here's the V inspiration photo (and yes, I realize this is chevron so not herringbone):