Fit 25" inch shower door in 27 5/8 opening

I purchased a dreamline frameless glass shower door (3/8" thick) and am trying to hang it on an existing porcelain tile (shiny type of tile) shower stall. it is on a 46" wide opening so there is a fixed panel about 22" wide and 72" tall and a pivoting door about 24" wide and 72" tall. Each piece weighs about 80 lbs give or take. The door hinge placement is about 2" over from the nearest stud, and to complicate matters the wall is a townhome party/fire wall with metal studs instead of wood presumably. The instructions call for screwing directly into wood studs behind the drywall and tile drilling 5/16 holes thru the tile. However a tech told me if it was close to a beam toggle wall anchors would suffice. Thinking thru this many times over I am less than optimistic wall anchors will work, and they require drilling enormous 3/4" holes in the tile. The other option is to cut a hole on the drywall above the tile and drop in a piece of 2x4 coated with liquid nails to secure it to the drywall. I would drill a hole thru the tile and use a woodscrew to pull the 2x4 tight against the drywall while the glue sets. If I use the toggles the 3/4" hole will lead to an verticle offset for the hinge placement so I would have to compensate by drilling the holes a little higher. Has anyone done this type of install before? Will toggles work without cracking the tile? Or do I need to do drywall surgery and try to insert a wooden beam?

I have small recessed medicine cabinet (14" w x 18" h inset measurement) that I would like to replace with a nice wooden one, rather than a plastic one found at a big box store. However, I am having trouble locating a recessed wooden one that will fit my small recessed area. Therefore I am thinking of replacing it with a wooden wall mount medicine cabinet. Has anyone had any experience replacing a recessed medicine cabinet with a wall mount one and if so, are there any tips you can pass along? Would I need to fill in the recessed area before installing the wall mount one over it? Do I need to do anything extra as far as anchoring in the wall mount one over the recessed area? Any info or tips would be greatly appreciated! Thank you!