Here's an update. I recently contacted an Italian lawyer through Trentini nel Mondo who clarified the situation. She said that there could be two ways for me to get citizenship.

1) My great-grandfather was born in Innsbruck but grew up and lived in Trento because his family was from there. Because ...

mler, that makes sense. Grazie.

I'll see about using my great-great-grandfather.

Hey guys, I applied for an appointment for citizenship at the San Francisco consulate with the intention of using Legge 379/2000 and I was told that I cannot use my great-grandmother. I specifically mentioned Legge 379/2000.

They said:
"You cannot apply through (your great-grandmother) because ...

Riccardo, thanks for your reply. I will be applying through SF and it's good to know the approximate time it'll take.

Hi, does anyone here know anyone who has obtained citizenship through Law 379/2000 yet? I'm going to apply through my great-grandmother and am curious how long it will take. Judging by what people have said here, I'm expecting a long time.