There weren't any compatibility problems between Zurich and CH Pro. The reason of the separate installers, is to give a better color matching for a smoother visual transition between the two. Installing the regular Zurich over CH Pro works nice, it's just that one will see more difference between our colors and the rest of the scenery.
So, if CH Pro is releasing a new version with winter textures (night it's not a problem, our Zurich for CH Pro already has night textures), I think the easiest solution would be simply use our standard version in Winter, and the CH Pro version in other seasons.