Hi Snoopy, yes the Ducellier dizzy is better than the Femsa because it is far easier to adjust the contacts, and also it can be converted to electronic ignition which the Femsa cannot be as far as I know.
Same "rumours" over here.
The "experts advice" is to get rid of the Femsa and replace it with a Ducellier ASAP.
I don't know, I tried both. The Femsa with points worked as well as the Ducellier with points.
Only when converted to electronic ignition the Ducellier won over the Femsa.
The 123Ignition I'm running now trumps it all though!
The Femsa dizzy didn't give any trouble, it worked fine, but I wanted to fit E I so I used a Ducellier on my GTL fitted with an Aldon unit, more expensive than the 123 I think, but it does a great job.