Indeed, Kodak sold aprons for each size of popular film so that the dimples in the edges would only touch the edge of a given size.
At KRL, we often were faced with processing long lengths of odd widths of film. This is how we did it:
We got a large graduate cylinder (250 ml, 500 or 1L for example). We got a rod and hung a film clip on thee rod and then we hung the film, emulsion side out with both ends clipped to the rod, making a loop. We then took a "C" shaped metal weight and we hung it over the bottom of the film loop thereby reducing the apparent length by 1/2. So, 3 feet (about 1M) of film was reduced to 1.5 feet which fit in a 500 ml graduate very handily.
Agitation was done by lift and drain using the metal rod with the clip attached.
After the Photo Flo step, we removed the weight and unclipped one end to hang the film up to dry.
Try it, it works. And this reminds me that Bill Troop and I were discussing a book or a series of articles on handy darkroom tips like this that I learned at EK.