You should have 2 x wall mount strips, the glass slips inside and can be adjusted in or out and also level them. Also a strip for the outer corner, for adjusting depth and angle. these angles are around 15mm deep so you should be right. The glass must be on the inside of the angle, the tile should be at least 10mm below the top of the angle. You can add a small PVC angle if the tiles are too high, just make sure you do not skimp on the sealant under this.
Good luck and fair winds.![]()