The Nighthawk line (and the related Track Havoc) are all pretty mild asymmetrics by today's standards. They were pretty middlin' when they were first introduced, but the Z-diffs for them have been in the 0.01-0.08 range, I think. The current NH has a mid-diff of 0.002". I think the Havoc was 0.007.
With mid-diffs like that, spin times are probably several tens of seconds. No 5sec spinners like the current crop of asyms.
SH