Is there any reason glass cannot be set on a shower base that has a built-in tile flange? I'm going with an obscure glass so you won't be able to see through the glass to see the tile flange lip from inside the shower and from the outside there will be a vanity up against it so that isn't an issue either. So the glass would be sitting on the tile flange just as tile normally does (and will on the other two walls of the shower that have tile flanges on them). For budget reasons I need to redo my already gutted bathroom in pieces and am thinking do glass on the entire side of the shower base where the vanity will butt up against it so I can do the shower NOW and later when I have the money do the vanity part of the project. If I had all of the money now I'd put backer board/tile on the side of the vanity and put the glass ontop of the vanity countertop but that isn't practical financially right now and I need a shower ASAP.

My glass tiles have a matte finish so even if they were being etched, it wouldn't make a difference. Unless your glass has some sort of coating on it, it's just a piece of glass, and glass is really tough stuff--if you ever go in a lab, all the really nasty corrosive stuff is in glass bottles after all. But test it. You never know... :)

Creative Tile Eastern CT: I can see that a custom shower base and such can be done for less money than a purchased base. For whatever reason, the details of a custom base seem to be problematic for a lot of people. There are multiple posts here of bad shower jobs - where they leak, the water doesn't drain correctly, etc. I know that an experienced person could do this and do it correctly. But I'd rather pay the money for the base and get that part, at least, right. There are other parts of that Tile Redi system that bother me: As a general practice you don't rely on caulk (even 100% silicone) to make something waterproof. The flashing shouldn't be an option where the wallboard meets the base. Likewise I don't like how the "Tile Redi Niche" product is flashed. The flashing around the product routes water to inside the wall instead of to the outside. It depends on caulk in order to keep the water from going inside the wall. The base of the product should be flashed to move water to the outside. The sides should also have flashing on the outside IMO.

We recently renovated our daughters bathroom, I found some quarter round made from vinyl... used it to trim around the tub and ceiling... super easy to use and gives a nice crisp line. If the gap is to big for quarter round there are other options. Honestly... the contractor should take more pride in his finished work...