""""""""I don't think you can put a smooth single surface in that spot - I think it needs to have a ridge down the middle of it to match with the sharp point on the other side.

Something more like put a line down the middle of it and then patch each side separately, see attachment"""""""""

Yes, i was working that, but couldnt get the surface to maintain tangency/curvature against the other ones (The existing blend and the body surfaces).. I was trying various sweeps and different ways to draw that "spine", but couldnt get a smooth result... I was wondering if ther was a Rhino command that would do this in this situation.

For instance, running a blend of 10 on these 2 curves here, gives a great result, but you can see it deviate away from the body, so thats not a good command for it.. Maybe when MoI gets a multi edge blend then these would be possible?