Howdy
Lots of guys in Cowboy Action Shooting put wraps on their levers. We are restricted to natural materials such as leather. You of course are not restricted to leather.
When I first started shooting CAS with my old Marlin Model 1894 (Made in 1895) I wrapped a leather thong around the lever. The same with Mrs Johnson's Marlin 1894CS.
Hint: If you are going to use leather, be sure to coat the metal with oil first. Ballistol is a good choice. Otherwise the leather may attract moisture and you may find rust under the leather if you remove it.
These days I don't have a wrap on any of my lever rifles. I took the wrap off my old Marlin after I had it tuned by a Cowboy gunsmith.
My main match rifle for the last ten years has been my Uberti 1860 Henry. I had it slicked up by the same gunsmith. I can shoot it all day long and the steel lever does not hurt my hand no matter how fast I cycle the action.
I used this Winchester Model 1892 as my Main Match rifle for a few years. It never needed a lever wrap, the action has been broken in over about 125 years and was very smooth without needing any slicking up.
After the 1892 I used this Uberti replica 1873 for a few years. It too was slicked up by the same gunsmith and never needed a lever wrap.
I have a bunch of other antique Winchesters which don't get shot all that much. But none of them has a lever wrap either.
All I'm saying is you might consider bringing your Marlins to a competent rifle smith. Most modern rifles (and revolvers too) are over sprung to counteract the internal friction left inside by the manufacturer. Once the bolt and other surfaces that rub against each other have been polished, removing a lot of the internal friction, a lighter hammer spring can often be substituted without loosing the reliability of being able to fire all brands of primers.
I have had this done to my antique Marlin as well as the Uberti 1873 and the Uberti Henry. I can fire them all day long and my knuckles never get sore from working the lever.