I'm playing around with mine at the moment, having swapped carb, intake manifold and distributor with R5, along with electronic ignition. The Ducellier I'm using is of unknown origin and mileage, even thought to be non-functional, so I guess it's worth messing with. Thus far, if I move it one direction - I'm not happy with the results...then I move it the other direction, and I'm equally unhappy.
What I'm trying to accomplish is to gain lower-end advance, since I only get a slight pinging at WOT and top speed. I'll fiddle with it some more, along with the mechanical advance springs, and see what happens.