Hi Dimitri.
You're welcome!

@You : "...Now as to 'zebra' analysis in Rhino... is there, really, a way of avoiding such surface continuity defects when working with so many filleted edges on a model? What may be the 'key' element, in modeling process, for avoiding such continuity problems in surface flows? Any related hint?.."

Well...what can I say ?
Unfortunately this particular area of Nurbs modelling is one of the hardest. I'm learning too :)
There isn't any thing like "push a button and do the magic".
To get a quality surface with a good and "real" surface continuity, there are really so many things that come into play.

As I said I'm still learning and anyway for thins kind of things I think I'm not the best Moi user around :)
On this forum there are some other power users a lot more experienced than me about this topic.

And of course all we have the excellent help of Michael!

Anyway, keep in mind that when it comes to play with Nurbs modelling, the very first and most important rule is always the same :
STARTING WITH GOOD CURVES PRODUCE GOOD SURFACES :)
All starts there : Good curves.

For that reason, as also Michael said, I suggest you to redo from scratch your model rather then adjust the actual shape.

You will learn a lot here on this forum. You will see :)

Ciao and have a nice day.