I would follow the guidance of either the producer of the various covering processes and/or what the aircraft manufacturer provides. If nothing is published, it may be worth contacting them directly.
We last covered our PA-11 using a Butyrate dope finish. The only surface on the fabric I put anything but soap and water on is the leading edge of the wings. I apply Shell's Flight Jacket cleaner and polish once or twice a year in order to make it easier to remove bug strikes. [I soak the bugs using a spray bottle of water and then wipe them off with a hand towel to do this].
With the covering process I used, wax on the fabric greatly complicates fabric patching or other repairs because solvents used to remove wax may further damage the fabric. Pigmented Butyrate dope is not "paint". My finish protection strategy amounts to hangaring the airplane when not in use.