After more research and consideration, I don't think the tower in your sketch is Tiergartnertorturm.
I can't find a single image of that tower with the "bay" on it - new or old. I suspect the tower in the sketch is one of the more generic ones along the wehrgang. Possibly Turm Grunes J pictured below.
Remeber Nuremburg was heavily damaged during the war and rebuilt over much of the next 40 or 50 years.