As she did spend most of her time in the atlantic, you can also use 32.1 Nebelgrau. This is a color very close to the light grey.
This is a tip I received from an WWII sailor:
Did you know how that they "prepared" the colors? Every vessel had his supply of white paint.
To obtain the color that they wanted, they added color pigments. So every time they mixed the colors it was approximatly the same color.
This was normal with the allies, so I think I can say the Germans used a similar system.
When I paint a hull, I always try to paint with several brands of paint, the color is almost the same, but when you look at the model, you can see that here are differences.
Kurt