Ed, I suppose that makes a heated garage a necessity in Canada?
Rather than cover the wings I use what are termed "clean condition suits" as used in aerospace or critical type environments inside rotating machinery such as turbines and generators (when not rotating!) The idea behind them is you can't inadvertently take anything in that can be dropped or fall out of pockets, and everything you do take into the controlled environment such as tools and measuring instruments is logged in and out.
That's not a problem when working round the Elan but the big advantage is they are very soft cotton overalls with just a velcro fastened front with no pockets, buttons, zips or buckles to catch on anything. Dab some wax on the wings and the car gets a polish at the same time