Where would you say does the NG2 neck profile fit in?
From my experience the NG-2 is much thicker from front to rear and sits full in the palm easily for most positions. It has a nice curvature to it that allows you to slip your thumb up if you need a little more articulation and crosses between the C & D shapes. I would call it a large flattened C shape. Compared to other basses I'd say it sits in the middle in terms of thickness. Also the curvature around the frets seems to be more pronounced but that could also be an affect from the wider shape.
The ABZ in contrast always feels a little skeletal in my hand. It's more of what I would call a flattened D shape. It has a lot of the same kind of curvature as the NG-2 but is just thinner overall. You can especially feel this up near frets 20-24. You also have a slightly different geometry in that area due to the neck/body joint.
I'm very interested to feel the profile of the Z neck. I got used to the Ibanez SR necks which are just as thin as possible and really liked them. When I moved to the ABZ the thicker neck threw me off for a bit but what I love about the Dingwall is that feeling of industrial strength. I imagine the Z's have that same industrial quality while being even thinner which should be very pleasant for me.