I don't have a Nighthawk but I have a TM-4 and a VS-4, and because the neck on them is the same, I think it's safe to say that's the same profile Sandberg uses on the Nighthawk.
It's slightly wider at the nut than a Jazz. I find it super comfortable and actually prefer the tiny bit of extra space between the strings, though it may just me in my head. The depth is thinner with a larger radius. Noticeably different and more comfortable to me. Last stingray I played, older US version, had a P-bass width and a tighter radius yielding a thicker neck... very much felt like a P-bass to me. The Sandberg neck does not.
That's great info, thanks!
I've got the shortscale Lionel and love the flat fingerboard. It's a 14" radius I think.
Was looking at possibly getting a TM 4 and wondered if the neck was just as thin and flat. If it plays anywhere near as good as the Lionel I'll be happy.