I'm crazy for borders and whenever I do a floor, I incorporate some kind of a border. I can't help myself. In your bathroom I would run a border an equal distance from the wall, from the face of the vanity and from the tub and then I'd jog it into the hallway if you want it to feel like one larger room or not if you want to articulate the hallway as a separate little space . I think those idiosyncrasies of the border jogging are part of what makes them fun though. Here is a picture of my border following the shape of a knee-wall bumpout to accommodate plumbing (still not finished but close!): And my tiny potty room, yes, part of the border is concealed - I don't mind! better picture of the border, bathroom less finished: And my kitchen floor plan with the border following every corner:

I prefer that the floor be pitched a bit more than the minimum 1/4" per foot. Because floors like this can be slower draining, I recommend using a topical membrane on the shower floor. When you set the sheets, be careful about the "sheet-to-sheet" lines showing. Dry lay them. Step back. See if you can see the 12" by 12" sheet "pattern". Sometimes it helps to peel off some of the tiles from the edges of the sheets and rotate or reset them to better enmesh the neighboring sheets together, it'll eliminate any sheet pattern. I recommend you consider using a grout darker than the color of the tile. Use a sanded grout. Be careful with cleanup that you don't rake the grout out of the grout joints, or the grout lines will hold water.

Hi - do you have some tight curves in your target tiles, or are they square? When we were building ours, my PB warned me that depending on the tile, the transition from pebble to tile may not look so good if the curves on the tile are too small for the pebbles to fit into. It is worse with mosaics, for example. But one thing to keep in mind when putting target tiles on steps - they can be slippery! We have one on our spa step and if you use the tile specifically as a target and step on it, you can slip! Now, when I step into the spa, I make sure to step around the target tile. Just something to keep in mind!

PRO: I have the privilege of bidding and estimating remolding and repair jobs for a really big company and we see A TON of pools (remodeled over 30,000). This is not a pitch for my services, but my advice would be to put in a pool grade waterline tile and grout it by professionals. Tile is not for looks, it acts as a system to waterproof your pool. As your water level raises or lowers (or stays the same if you have an autofill) at some point your pebble will be exposed to air. In a perfect world about 3 inches will be exposed if you keep up on your water. A cementitious surface for your pool is meant to be hydrated as it cures. Total cure time is debatable, but I've taken classes where some experts think total hydration can take years. I'm sure there are cases (like the one above) where pebble can last 25+ years exposed to the elements, but there are of other factors that might of helped this rare occasion and I'm sure its not just cement strengtheners being added to the mix either. I find cracks in pools and problems with pools that owners didn't even know exist, everyday. I show them, and they all say "Wow! Now I see it, never even noticed that before!" Most often (depending on installed coping) we see small hairline cracks form at the base of the coping, they can run vertically or horizontally. Our solution is always to reset any loose coping (if cantilever or poured in place install a silicone joint) choose a thin tile (if not doing a re-pebble/re-plaster) and get new waterline tile in. Just my take on it from what I've seen. Feel free to find me and private message me if you would like more information. Please do not let pool builders convince you it will be fine, we are the guys out there cleaning up their messes and fixing the problems they never see years later.