I've grown quite of few Short Riders with excellent results (organic soil, 400 MH then HPS at soon as they start showing pistils). It's hard to say without knowing more about your set up...but yeah, should be a little further along then they are. Anyway, these guys hit a certain point and then just go apeshit. It's pretty amazing.
My only suggestion is to start them immediately in 2 - 3 gallon pots. I don't transplant mine at all. They will thank you for it. I've been pulling 1 - 1 1/2 oz per of good solid dry nugs from mine. I think if I dialed it in right I might be able to do 2 oz per plant...maybe.
Good luck man and enjoy!