Sorry it's too late... I used black pipe through my whole shop - ended up tearing it all out and re-doing with copper. I too have a "lift" to the main run - with a slope - and risers off all of the take off points - and drops for the moisture/collection - and water separators at each regulator..
When I paint - I use a section of hose off the regulator that is full of desiccant.
There's drains at every run - and when I open the ball valve - I guarantee there's moisture that blows out under pressure. That would include both the main runs (ball valves at the end).
I live in a MOIST area (Pacific NorthWET) so rusting stuff is an issue to start with!
