"back edge on a wooden strip that would be affixed to metal studs behind drywall. " This is generically called a ledger strip. It allows the placemet of fasteners as needed to support a load that is along the whole strip. If you anchor the ledger strip to the steel studs with suitable fasteners it is not going to come loose from the wall. Toggle bolts would probably be acceptable, but screws that grab the stud to hold the ledger strip are better. Self tapping sheet metal screws at least the thickness of the ledger + thickness of drywall + a 1/2 to 3/4 inch would do well. That would be 3/4 + 1/2 + 3/4 = 2 inches for a 1x ledger strip.

There are a couple of large apartment buildings in my city from the late 50s early 60s that are beam and column construction, and none of the interior partitions have studs. There are some units that have masonry walls in between, others have this strange "fireproof" construction where strips of drywall were used as "studs" and two layers of drywall were glued to each side. Some of the partitions within the units are layers of drywall or some kind of panel and are less than 2" thick. Some walls have conventional outlets and some are in surface mounted boxes. Most people who renovate these units now tear out the partitions and start from scratch since rewiring or anything else is a nightmare.

Have you found the studs, using a stud finder? If your building has them, that's what you want--the studs. also, to throw another idea into the mix, my 1921 apartment building (a co-op, which means I own my apt, which means i don't need my landlord's permission to put holes in the wall) does not have studs OR wood lathe. It's plaster (about 3/4" to 1" thick) over metal, over brick. No brick on the INSIDE walls; I think those are either true plasterboard or plaster brick, and they hold themselves up; again, no studs. Don't ask me why, or how it all hands together, but it's been standing quite sturdily since 1921 and there are NO studs. Framing around doors, but no studs. To install Elfa-type shelving, we used a hammer drill to drill into the brick (about 3 inches below the surface of the plaster) and Tapcon screws (intended for installation in concrete) to fasten things to the brick itself. (I thought I had found a stud, drilled into it, and discovered it was the BX cable for the electrical wires--fortunately, I was acting sort of gingerly and didn't pierce the BX) I *did* however hit a gap and the brick (which I couldn't drill through w/ my wood bit). what helped us a lot was that someone else in our building had renovated, and had pictures of the "inside" of the walls (there isn't an inside, really). And, that my "uncle" had run into this construction before as well; fortunately I called him for advice, or happened to speak to him on the phone as we were trying to figure out where the heck the studs were. Ask around the building and see what other people have done, and what they know about its consstruction. (if you're renting, you could ask your landlord,) Also call anyone you know who has done DIY in a SIMILAR AGE of building. I will say that our kitchen cabinets are mounted in the plaster-brick or plasterboard walls w/ anchors, and they're very very sturdy.

I have a single very expensive stud finder that works on plaster, but it will mess up if expanded metal is present. Expanded metal was used to strengthen interior corners, hold metal bead on exterior corners, and even as the entire lathe in place of wood strips. By a couple 1/16 inch drill bits and start hunting. While nominally on 16 inch centers, older house often wander a little. Measuring can give you a place to start drilling, but you need to verify the stud location at the exact height you want to anchor. The lightweight spackling putty makes short work of filling the small holes. the drills will quickly be dulled, and not be useful for anything else without sharpening. Save them for future use. They can be pretty dull and still work in plaster. The plaster will