I author DVDs myself as well, but only from stuff I capture via PVR or d/l in pre-made .AVIs, and I like Ulead DVD Workshop 2.
Does your Godfather set cut the showing of characters having flashbacks and move the flashback scenes to the first disc, in chrono order with the family story?
My pals I were a bit disappointed with "Spider-Man", so I thought it would be cool to cut the second half of it off and attach the first half to the sequel, with only a bare-bones bit of flashback-type review over the whole 2nd half of the first film to segue to "Spider-Man 2".