I noticed your roadie cycling kit your photo. I keep old road and mtn bike tubes of various thickness for just this type of situation. A small road tube should be just right. Snip the width to fit the knob and slip it on. Using car or bike tubes like this is called Ranger bands, I believe after the Army Rangers. They can even be chained together if the inside diameter is not large enough for your purpose. On another thread on CN, a member described how Don Pensack told him how to use the band to put on the eye piece instead of a tall eye cup - pretty ingenious.
P.S. I am registered to do the Ventura Cool Breeze in August, do you do any of these types of rides?
This is a great suggestion! Unfortunately, I recently threw out a bunch of my holey tubes and will now have to wait for a new flat, LOL. Or maybe check with some of my roadie friends.
I ride with the Conejo Valley Cyclists out of Westlake Village but have stopped doing Gran Fondos and other organized events, other than club rides.
I rode the Cool Breeze back on 2018 but no plans to ride it this year.
Enjoy, have fun, hydrate and stay safe! Rubber side down!