Over the years I have looked at various ways to produce an eccentric reducer with it's correct profile but have not really found an optimal method yet, here are the methods I have tried so far.

(1)lofting a number of circles that make up the profile
(2)extruding the straight parts at both end and then fitting a frustum of an oblique cone between, boolean adding and then doing a reducing fillet radius on the junctions of the straight ends to the oblique cone frustum intersection.

How would you approach it in Moi to achieve the smooth transition as shown in the images below?.