Thank you Marco for the quick reply !
What I wasn't happy with using the front/back curves as rails was that I was loosing the radius at the 3 & 6 o'clock positions. What I did was add a radius profile at the 3 o'clock position and use it as a scaling rail and also picked 'maintain tangent' and it looks like what I wanted !
Thanks again !

...with the maintain tangent option those radiuses should actually be "there"..even without the additional(3/9o'clock) curves..