does anyone know the difference between the seats on the iron and nightster ?

from the photos the nightsters seems to be a little bit shorter and doesnt but up to the tank fully.

I really like the look of my iron seat , but could do with being a little higher and further back to take the pressure off my back.

My bike also came with a dual seat which i tried today and was much more comfortable, however I prefer the look of the Iron type solo seat.

Any sugestions will be much appreciated