Fastbuds would have the quickest autos. Ganja Farmer seeds has strawberry pie and they claim it's a 56- days. She's full of ruderails. The more RR in theory the quicker it should be.
70-90 days is the the norm. It really all depends long the veg is. Like some autos might only veg for 3 weeks and might take then 40days in flower..Or if you stall an auto during veg you might prolong the veg by 2-3wks. 50-60 days on top of of veg.
Again FB hv a few beans that they claim is 56 days. They say that on banana purple punch and she's a real quick grower. I'm only on day 15 and I was able to top above the 5th node. But, I still can't c it been done in 56 days.
Anyways bro. Good luck