AMD announced, back in Sept., that they were starting production of these and they would be out in 3-4 months. May want to check status w/ them.
You got there first.
What is your shop temp/metal temp at? Probably goes w/o saying (as I see your following recommended dry times), but now that cold weather is here doesn't take much to slow evaporation of wax & grease remover or flash times between coats.
Black pipe is the way to go. Never PVC, as already stated.
The sizing will depend on how long your runs are. Taking into consideration pressure drop the longer it is.