To make our walls perfectly flush, our shower wall needs to be floated but the tile we want to use doesn't have a bullnosed version. As such, we were looking at Schluter type edges. If my tile is 1/4" and my set also 1/4", can I just pick up a 1/2" Schluter type edge and have it envelope the tile and the set so it is flush against the wall?
Your mortar probably won't be 1/4" once you press in the tile. If you're careful it'll be not much thicker than the flange on the edge molding, so you generally purchase an edge with a depth matching your tile's thickness.