Since you already have couple nautilus, why not consider the leather strap version 5726A. Some said the annual calendar is more a dress watch feature so it suit more with a strap and I believe is easier to source one too
Always interested in the Zeitwerk. To me it is a must have model in every Lange collection (apart from Lange 1 and Dato). I do noticed some issues regarding some early models has “sudden” jerk move of the minute plate and the watch stop for no reason...etc. Want to hear owners opinion and share your