The ones I’ve worked with were unperforated. Lengths are quite short by motion picture standards.. standard size is 100’ of 35mm film, on a reel ~4" in diameter (don’t have one handy to measure).
I like the multi size roller design… I’ll have to print out a few and dig up my test reels.
The library microfilm transports are generally quite simple.. reels, one or two rollers on either side, and film goes between two glass plates. Typical:
-Bob