JRE---Thanks for sharing your experience (s) with having probably the (possibly) extremes CONUS Winter weather. I put the hardtop on our SL the first Winter we owned the car. Didn't really notice anything intolerable with the way the soft top and windows looked the next Spring, but I did ensure that the sun was shining brightly and the temps were warm when I deployed same.
I do feel that you do best what you do most often and the old saying "Use it or lose it" can apply to most any car that sits a fair amount of time. Accordingly, I tend to push a lot of buttons when I take to the road---save for rear window de-ice and traction control (snow-chain button). Comprende? Regards....BAMeyer