Mech - I'm not sure of the formulae necessary to consider losses due to compressing air, but I do know that it's a very inefficient process in most cases, given how long it takes piston pumps to provide X volume of compressed air.
I do know that if you want to measure the mass of a tank of compressed air, you consider:
Volume of vessel*intake CFM*compressor efficiency/time empty to full
You end up with:
M = V*I*Ce/T as a formula for calculating the mass of air inside a vessel, when you don't know the pressure. (Obviously, if you knew the pressure, it's a much easier process.)
Mech - Never let anyone take advantage of your "lack of formal education" either. I quit school in 10th grade, 1st semester. Just make sure you never stop learning, and you'll be fine.
I'm can't say much about your design, because I'm not all to familiar with the design or theory of operation. I'd like to read whatever writings you have on it, though. (After the Patent, of course.)