2.5 a plant is easily achievable with the right environment & equipment. My first Automatics yielded just over an oz each but they've been steadily increasing the more I learn about growing. I found that getting the temps/humidity/light balance is the real yield producer in my groom. But that's something I've only recently achieved.
They're just regular autos so you can have them on any light regime you wish. I prefer 24/7 these days. Seems to reduce stretching and speeds up growth a lot in my opinion.
In hydro and with some LST I reckon I could get 5 oz a plant. I'm certain of that. Then again, many other auto strains beat these hands down on yield, like Maxi Gom or Critical Mass.
Also, the MI5 seems to be very, very highly rated around this forum so don't pass up the opportunity to look into that strain.
This is them. They could have been SO much more, too. They started off life under a 12/12 regime in my photo tent.. so they stretched a lot.. and they've also had a nute overdose a while back, both of those things really knocked out a lot of yield.. but they pulled through ok and now they're under a 400w MH or a 600w Dual Spec bulb (I alternate depending on ambient temps) and are producing some really dense nugs and colas. Big isn't always better as it's the dense weight that we're after really.
Now I've worked out the maximum feed for that strain I'm gonna smash those easy next time.
2nd edit: I've just realised that a week ago I estimated their yield between 1.1.5 oz but they're packing on weight in their last coupla weeks. I may be overestimating it at 5 between them, maybe 3.5-4 but it's my best guess going on past exprience.