This is my first time growing autos. I have fast and vast they are doing very well I think personal. I have seen others on different threads that are a lot small than mine. I put them in dirt after germination on April 19 2015 and my tallest one is about 39 inches tall and the others are not far behind that. I use 15 gallon pots OF dirt and nectar of the gods feed. I also run 3 1000 watt lights.
I grew these outdoor last year and yours are gonna be huge. Make sure you got about 5' clearance above them.