I simply tapped into the existing Inspiration diluent manifold, so it was using the normal first stage gas provided by the onboard regulator.

Not that it really makes a huge difference, but the system I built used the standard modified wings inflator for adding gas, and I retained the quick connect. Theoretically, any gas could be plugged in there, and as it's a completely redundant gas addition pathway, could be used as a substitute manual add valve if the main rig manual add valve failed. Either diluent or 02 could be fed to that port.

Dave