network surface like loft definition - almost works, but not quite

Sorry, bit of a long story to explain something which is essentially simple. Bear with me.

I was looking for a way to define a parametric double curved 'body' of a product, like you might see in a shaver (though not as ugly in my example file, I hope), in grasshopper. Typically I would do this in rhino with a network surface, or perhaps a loose loft with a lot of cross sections.

To avoid having a lot of cross sections to define, I thought I'd be smart, and use curves for loose loft in the length direction; 4 would already give me a lot of control over the surface.

However, if you can't control the orientation of the isocurves in the 'cross-section' direction, you can get an ugly, ill-defined stretched surface, typically if you go 'around a corner'. So, I added guide curves (the green ones) in the side view, that split the loft curves - so you divide the surface in smaller parts, essentially defining where cross sections are going to be.

It almost works... but it turns out, the surfaces are not quite tangent when the curvature gets bigger, as the zebra analysis pic shows. Such a shame - otherwise it was working perfectly, and a very simple way to get a parametric 'network surface' like definition in GH.

So:

1) Anyone knows why it isn't working, why my surfaces don't stay tangent, even if the loft curves of the respective surfaces are perfectly tangent (as they originate from one curve, split into several)?

2) Even better, know of a way to solve it, or at least create something similar that does work?

Thanks very much, Michiel