When I changed out my glass shower doors I did the RV and House at the same time as I needed more room for my shoulders and in particular for the RV after having some significant shoulder surgery (I removed the doors prior to the surgery). I went with an extend-a-shower type of curtain that provided a lot more shoulder room.
The rollers were not the reason or a concern really and I never got hair or soap scum on them as even the lower rollers didn't actually ride on the bottom or even support the glass panels and instead it was similar as to in the image below which would keep the doors in place. I share this just as fyi and acknowledge that I may be confusing the house and RV's glass panels, and as the OP stated he doesn't believe his have lower rollers which means that my information wouldn't apply. However, I thought I would share why they didn't get rolled up in hair and scum which is because of the design which was similar in concept to this design and how removing the bottom roller for this design is all that is needed. (again, I now realize this isn't the case for the OP) ~CA
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