I just don't know which kind of curvature can handle -NSIDED- tool

Avoiding misunderstandings i cleary speaked about G-2 why? Because it's only option that gives a perfect junction between two surfaces
This means(one more time)that you can't see seams or artifacts in junction area...it's perfectly smooth(continuity of curvature)
If you want better know about, here is a link of SOLIDS++ kernel that MOI use:

http://www.integrityware.com/solids.html

and here some examples of continuity options from them:

http://www.integrityware.com/AdvancedSurfacing/Blending.pdf

I posted that "limit-situation" based upon example of Futagoza (Stefan)
That time,Michael well noticed seams at first close-up and speaked about not perfect junction
I know..NSIDED can handle my " limit-example" but also give a not perfectly smoothed surface