We used 12 x 18 tile with a 1/3 offset. We laid it out on the floor to calculate our rows, starting with the travertine base molding and working up 5 rows before starting our 4 x 4 accent tiles. This left us with about an 11" or 11 1/2" row at the top where the difference is hardly noticeable. We decided that it would look best, and certainly be easiest, not to try to bring this row around to the wall were the tall niche is. Instead, we cut a couple of very large tiles down to a size equal to the accent row so that we could maintain the grout lines. The tall niche was framed in but we didn't finalize the location of the shelf until we knew exactly where the rows of tile would line up. The smaller niche is in our pony wall. As you can see, we put a bullnose on the outside walls of the niches and then cut a tile to line up with it on the inside of the niche walls. I'd prioritize a deeper niche over avoiding a vertical grout line. As long as you have a solid piece, whether it be granite, quartz or tile on the bottom, I wouldn't be concerned about vertical grout lines in the niche. As far as the size of your shelves, I'd want to make sure that my largest bottle could fit with some room to spare. My niches were designed to accomodate my Costco size bottles and I LOVE them! (My son had just taken a shower before this picture was taken so the grout is darkened from the water... not mildew!) I hope this helps!

Nice pics of your shower Raehelen. I did the same thing, split the difference between the top and bottom, centering my centerline of 9, 12" tall tiles, along the horizontal center of my shower. I have 8 foot ceilings too. I am going to be working on my niches today to hopefully finish this stage up. We just got back from a week long trip to Seattle (I waved at you Raehelen ;) So now its back to work. Mitering corners was one of my thoughts about turning a corner. I haven't decided yet how to treat the corner of the partial wall. Regarding my niche, I just overlaid the perpendicular 4" niche side tiles with the fitted field tile. I have two more cut surrounds to do for the face of the niche. I wasn't going to put the bottom sill on last but now I am. I wanted to have it be first so that the tiles would set on top of the sill and then water drain off with the slope. But I had 2 options of stone for the sill and I am going to put it on last so that I can use either option. I have a modified shower curb for one option and then I also have a 4" deep 3cm marble that would match my counter. The 4" would have been too shallow to set it first then tile around it. The shower curb is more like 5-1/4" deep. The left over marble was due to a mistake on my first counter. They had the backsplash left over so I kept it. I hope it will not be a problem with my revision. I will caulk the seams of the sill, but I don't think it is ideal. Now I have the option of putting in the shower curb or the remnant backsplash for my sill. I never asked anyone about this installation change. I looked at a bunch of pictures and once in a while saw the sill installed in this order, especially if the sill tiles were the same as the field tiles and all the seams were mitered. Note the permenataly installed tile wedge :/ I put it in backwards to take advantage of the widest part. Now it is stuck in there. I will have to cut the darn thing with my Fein Tool.

How about just the bench and getting a great basket or tray (that drains) and putting your products in it? That way you can get both. This might work especially if the bench is at least partly shielded from view from outside, if you care about your products being out in the open. The niches are useful but they do take some extra cleaning and I have to say that I don't love them. (there have been threads on the value of niches--people have definite views!) The bench is a really nice look. I am not sure how much anyone really uses it to sit (maybe as I age, I will sing a different tune) but it is nice to prop up the leg when washing or shaving.

I guess I could drill holes in the tile/backerboard for specific shelf supports, but I really wanted something more seamless - like supports that are part of the niche design where the niche would look just as nice without shelves. The idea is to use the bottom shelf for soap, etc. and only add additional shelves if the person using the shower wanted to trade elbow space for storage. If I can add a 3” niche on back wall, there would be 35” of width vs 32. Front to back, it’s 30. So every inch counts. (Shower head and valve are on right wall of u-shaped alcove.) EDIT: I might be able to find some kind of tile edging to screw into the sides to use as shelf supports.