It's simple. And as a bonus, PP blending with N2 doesn't require oxygen clean tanks & regs.
...what? Are you saying you don't have an N2 tank?
I am embarrassed to say I don't, but now that I think of it, I should. My newer car came with its tires filled with nitrogen, and it was recommended that I maintain that practice. Stopping by gas stations to top off tires when they are low has forced me to substitute a 78% blend--hardly ideal, but the best i could do.