Like, what FF went the fastest for you?
For me it was FF13. Took me 40 hours to get to the final boss, however, I lost 3 times in a row and didn't fight him until about 60 hours in.

If possible, I would like to leave out certain games in the franchise do to their in-complexity, like FF1,2,5. Those games I have beaten in about 25 hours, however, the remakes of FF3,4 left me more hours.

Usually in FF games, about the 70 hour mark for me is the final boss, and about 104 hours is he final super boss.

Longest would be FFX. For somereason, it's story makes it feel abnormally long in a good way, and one of the only FF games that left me sad, and wished it continued longer.