With the long run on your returns, I would definitely research before trying and probably run the math. I am thinking that the pressure is highest at the pump, and then decreases with elevation. So you may have 10psi at the pump and then 1psi at the outlet. The nitrogen would be compressed at the pump and then start to release as the pressure diminishes. The question is, how long does it take for the nitrogen to release, too avoid supersaturating your DT? I don't know... Has anyone made "dive tables" for tanks? lol jk, but I think the same concept from scuba diving might apply here.