Hi.
First of all, congrats for this fantastic bird!
I would like to suggest the following detail, in order to get the plane even more realistic:
In the real planes, when the oxygen test is performed, the total amount of oxygen falls a little. I think is easier for developers to introduce an entry for dropping the quantity, e.g. 10 psi every 3 times the botton "Test/Reset" is pressed in normal or 100% mode, or every 3 seconds it's pressed in EMER mode. It's just a small detail, but these things make a unique airplane.
Thank you!
Antonio.