Hi David,
Good initiative with this thread!
In general I avoid the “split” approach because Rhino is having problems with NURBS corners where u- and v-directions are parallel or tangential. You’ll notice when you for example offset these surfaces:
I think Rhino should handle these cases better in the future because when you convert a SubD-Ngon ToNurbs then you’ll also get exactly such a corner.
Anyways I’ll avoid it because other NURBS applications downstream in the marine industry also fail to handle these cases.