Floppy disks again

Hey, with the discussion of diskettes recently, and my own search for info on RX50's, I was a little surprised by the lack of available info on single-sided single-density 5.25" floppy disks (emphasis on SD). Were they ever actually manufactured, or was SS/SD strictly an 8" thing? I seem to remember seeing SS/SD 5.25" way back when. Can anybody give me an authoritative rating of their coercivity? Were they 300 Oerstedts, just like DD? If so, what is it that made them single density? Something about the size of the individual magnetic domains maybe? Or were exactly the same diskettes called "double density" when we figured out how to make drives to handle that? Also, my web search lead me to conclude that a 360K DS/DD floppy should probably work okay as an RX50; the only difference seems to be the number of tracks per inch. But they write many times more bits per inch along a track (maybe over 3000bpi?) than they do tracks per inch (48 vs. 96), so the media itself must have high enough resolution. Are the magnetic domains long and narrow and aligned radially? Or is there some other reason that it gets less resolution radially (tracks per inch) than longitudinally (bits per inch along a track)? If the precision of the drive is the only limiting factor, then DS/DD should work perfectly fine as RX50s. Clues are welcome. Cheers, Bill.