I want to add shelves and storage to my closet. The idea was to install battens along the wall and then lay the shelves on top. I only have thin metal studs to work with. On the left wall I only have two studs and they are in the corner. Should I use some kind of toggle screw into the metal studs or is that not a good idea? If not what is a good screw to use with the stud? What screw should I use between the studs? Shelves would be 1 73x23 (more like a desk) and probably 2 73x14 shelves.
Metal studs, like wood studs, should be spaced at a consistent distance, except for extra studs in corners, around windows, etc. That distance will typically be 16" or 24", so for a 73" wide desk/shelf/cabinet/etc. you should have no problem mounting to 3 or 4 studs.
As for how to mount things, toggle bolts make sense to me - I have used them myself, but it has been a while as I don't often deal with metal studs.
I would not recommend:
- Screws into metal studs - they only get a very thin layer to grip. Fine for lightweight stuff, but not for desk/shelf/cabinets.
- Toggles or other anchors only through drywall - you really need to get into the studs. Drywall by itself is simply not strong enough.
You don't need screws between the studs. Screwing the batten properly to a stud at each end (depth-wise) and at least 3 along the back edge (width-wise) will be plenty.
As for screwing to metal studs, this answer about using sheet metal screws is excellent, and there's more useful information in that Question including an answer from me about using toggle bolts, if you want ... but I'm recommending the sheet metal screws.
Your 24-inch shelf might be a little bouncy along the front edge. Depending on what you use for the shelf and what you're putting on it. You might want to add something to stiffen it.