You don't cut tempered glass. You measure for it to fit right in the first place. Was it ordered "based on a plan" before the tile went in or did the glass installers wait until after the tile installation to measure as should have happened?

The design and installation failed on a couple of levels. There was certainly miscommunication. If you want something, print out the photos of the patterns you like and show them to the tile installer. In a perfect world with a well-coordinated GC running the show, the tiler would then stipulate what the dimensions of the rough framing need to be. Then the wall gets built and everything is mighty purdy. For the top of the pony wall, subway-sized tile on top is going to clash pattern-wise with some part of the bathroom. I'd go with a slab of stone. For the face of the pony wall, there's no reason they couldn't have been tiled on the horizontal, even across the front. But my first question would have to be: are the courses of tile on the shower side of the pony wall and the bathroom side of the pony wall at the same elevation? Had he tiled horizontally across the front, would that front edge have matched up with the tile on both sides? That's probably why he ran the tile vertically up the face of the pony wall. Because the horizontal courses on either side of the pony wall don't. At least they don;t appear to as I view the photo. If both sides do match then the front could have been tiled, but If the width is longer than the tiles are, then you'd certainly have grout lines. If you can't use bullnose, then they could have mitered the tile which requires care to provide a bit of an eased edge, but it can certainly be done. Or use a schluter-type of edge, I think livewire or someone else mentioned that. Or use a vertical quarter-round. The nice designs don't usually just happen. But they can happen with proper planning. Back to the installation as a whole. I don't understand why there's a sliver of tile for the first course of wall tile within the shower (to the right of the pony wall), and a half-tile (or less) for the first course of wall tile outside the shower (to the left of the pony wall). Or why the courses of wall tile on either side of the pony wall don't match up elevation wise. I would have also had the overall height of the pony wall fall on a horizontal grout line on the wall. But overall? If you had a tile pattern in your mind that you liked, you have to share that with the installer. Pictures work better than words.

Yes, with proper bracing and good caulking it is possible to put a pony wall on the edge of a neo-angle shower pan. However, I would highly recommend using a solid surface product for the walls and have the pony wall attached on three sides. Also assure that the wall is built thick enough to support the glass hinges. I would get the glass company involved at the start.

"So you think it would look and feel less cramped with curb on the right side too? (been wondering if its just me and if it would really look better." Personally, I'm not certain how it would look. If it was open to the right of the shower, I could see curb to ceiling glass working. But with a vanity on that right side, some folks object visually to a wall of glass next to the solid side of the vanity. The visual from inside the shower can look awkward as well unless you're a nifty cleaner. "I dont like how they tiled the curb and top of pony walls either. Seems to me they could have use a long side of tile and have no grout lines ... If your tiles are long enough to completely cover the top of the pony walls with no grout lines, that would have been a nice move. I can't tell from the photo, but I'm not certain that they are. Because of that, if they did run them the long way, you'd have an orphaned grout line somewhere on the top of the pony, not lining up with anything else. I think what they did was proper, carrying the grout line from the two sidewalls across the top of the pony. What Nancy wrote in her previous comment is most common, carrying a material from another horizontal surface in the bathroom over to the pony walls and curb. It depends on where the glass will be set, but the tops of the ponies may see water. It's common in that case to pitch them (as well as the curb) slightly into the shower for drainage. The curb, they could have run the tiles the long way...but they lined up the tile layout and the grout lines on the curb with the tile and grout lines on the back wall. I have to say, I think they did a nice job marrying up the layout so it all looks ordered and cohesive. "We want them thiner too. " Was there ever an intent to use the top of the pony as a storage shelf? Shampoo, soap, razor, etc? You can have the ponies made thinner, but that's a whole new can of wax, a serious discussion to be had with your GC. Good luck with it, I hope you find satisfaction in the end.