Little pinch trouble using 2 rails sweep.

 From:  PaQ
4650.1 
Hi Michael, (and moiers :)),

I'm having some trouble to reduce the pinch effect on this specific example.


So I sweep the red profile with the 2 rails (blue and orange).
Ultimately I would like to use the green curve as scaling. The poles pinch are allready visible even without any scaling.

Is it any other way to getting something close to this shape ?

Thanks for you input.

EDITED: 3 Dec 2015 by PAQ