Tween between curves by fields

Hi there!

Using the new "Tween between two curves"  Rhino 5 tool, I started to get several issues when curves became kind of complex (I mean, concave and convex at the same time) and they weren't simple ovoide-like curves. 

The usual (and evident) methods for recreating this tool (or former meancurve tool) on Grasshopper like this (http://www.grasshopper3d.com/forum/topics/tween-curves?page=1&c...) kept me the same problem.

The only way that has been somehow successful is sort of sophisticated (at least from my point of view for such a simple routine), but it seems to be the most useful for a wider kind of curves.

It is made by creating field lines between both curves... however, time performance is not the best for sure because of the field lines component.

Apart of some minor adjustments, it works fine.

However, anybody can think about some improvement or any other most efficient method?

Thanks!!!