I've got a joddler in the garage, only used a few times on my friends Daf.
Hadn't thought of using it to do your roof section, but it must make offering up alot easier!!
The only isse with the joddler would be the moisture ingress from the double skin, but if you're seam welding the roof then thats not a problem. Might be a very long term issue, but then all fiats are a long term rust issue!
Did you go for manual or electric sunroof?
Cheers
Michael