Kodak used to make a roll film tank that used a dimpled plastic "apron" rather than a spool. So it could take any width film up to about 120. The dimples kept the plastic separated enough for the chemistry to get to the film. I've seen similar tanks from Japanese suppliers, but don't remember the brand. Not sure if any are currently on the market, but they are probably around on ebay.
The downside of these is that you can get scratches from the film rubbing on the plastic, and the plastic gets brittle and stained from the chemistry exposure. Reels are easier, but the aprons get around the exact problem you're facing.