Well I got this all wrapped up this week. I got the 3/8" steel tubing to plumb to the tank. I ran a small bend section from the tank and then a long section from the manifold back to the small section and used a union to connect them.
1. If I did it again I would not use the steel line (or maybe a smaller diameter). that 3/8" was a freaking pain to work with and bend with my plier style tubing bender. although it fit great into the mandrel, getting a collapse free bend was damn near impossible and detracts from the looks of it.
2. my orginal manifold design idea was crap. it was small and concise, but when I got everything connected and pressurized the system (I used the garage compressor to pressurize it to help located leaks without the running vehicle ambient noise) there were too many leaks that I could not get rid of. I ditched that for a straight 7 port manifold. it is still clean, but much simpler and worked on the first pressurized test.
I am very pleased with the way this came out. it fills the 1.5 gallon tank super quick and it aired my 35 from 20psi to 35 psi in no time flat and used the impact to crack the lugnuts off. I do have a fitting to run a gauge and make the tank connect horizontal but haven't decided if I will use it yet.
also I picked this up at the scrap yard last week for free as a jumper tank if I need more capacity
new manifold setup
I ran the line under the body and up in the rear passenger wheel well and secured it with line clamps