Hey Ponch. I have the Vision 17.5 aluminum wheels. As directed by Doubletree, I asked Tredit Tire & Wheel about the torque. Tredit advised to torque at between 175lbs and 225lbs, with a caveat that if it were him, he would go to the higher side. On that basis, I torque at 200lb ft.
I don't know about Alcoa Wheels. My axles are Dexter, and I did look at their torquing parameters for the 5/8 studs. Dexter states that their 5/8 studs can be torqued to a max of 325 lb ft. So, for me, it was just a matter of what was right for the Vision wheels.
You might start looking for a good "cheater bar", if you are going to do the torquing.
Good luck!