upstands

Hi, I want to fit a shower tray with upstands into a corner against 2 walls, which are going to be tiled, with a glass enclosure on the other 2 open sides. All the trays seem to have 4 upstands, but I only need upstands for the two edges against the walls. With an upstand on all 4 sides, when...

I’m tiling the dormer using concrete plain tiles, but I’m stuck on the inside corners. On the outside corners I used the 90° tile corners that come in pairs for left and right but on the inside, what type of flashing do i need? Specific type of soakers? I know you can get inside corner tiles...