The person who owns that shower is actually someone I met in this forum-- Staceyneil. We still never did figure out what the real cause was. We HAVE ruled out alot of things, but the one thing we know was a problem was moisture somehow holding suspended in the mud bed. I DO have a fix that I'm confident will take care of the problem, though.... as soon as Artistic Tile sends us some tile we can use!! :-( As for calming your fears, I really can't. That pan was put together the very same way I've put every shower pan (except Kerdi showers) for about 11 years now, the only update being the preslope under the membrane. This is NOT the only natural stone shower floor I've installed, either. But it IS the only one that's shown dark spots the way it did, and I can find no reason for it. The best thing your contractor can do is to make sure he puts a real good pitch UNDER the pan membrane, so that no water sits in the shower pan. The other thing is to make sure he puts gravel or spacers around the weepholes at the base of the drain in the flange, to make sure the weepholes don't plug up.

Never attempted to take out tile in this manner, but if I were going to try such a precise project, I'd buy a reciprocal saw and a diamond blade to cut the exact shape. If I were you, I'd also consult w/the local flooring people, specializing in tiles b/f starting the project.

Monrovia mom, I have a feeling you may be overthinking this. I have to preface this by saying this should be done to YOUR taste, not mine. But I'm thinking you may be disappointed afterward, doing what you're proposing. One stripe at say eye level, and maybe even a second at knee level if you really want to see a lot of the glass. But to have a stripe going horizontal, and another going vertical, and still more in the niche-- may become so busy as to be distracting. If you really want to do a lot of the glass, try something like this: As for doing the niche, and it showing as being off center, I think once you've had it there for a while, you won't even notice it, unless you're someone who is extremely detail oriented (read that as OCD :-)) Seriously-- overthink this, and it can drive you absolutely nuts. As for the water solubility of the glue, almost ALL glass is mounted with glue that will soften with water. Makes it a little touch on the installer, but not even close to impossible to work with. Once it's set, though, the thinset will hold it in place in spite of the mounting glue.

You paid for Walker Zanger tile in the first place. Is there any way you can send them the tile and have them lay it out again and paper the front for you? After all, the paint has been removed and the tile is intact. I understand that you're keeping the same installers in part because they are picking up the tab for replacement tile, but if you can salvage the WZ at this point, maybe you should have someone else install it. Cheating indeed. Jeesh.