Coffman,
the highest I can remember being in a Hastings was 22000 feet and neither the crew nor the a/c seem to enjoy the experience. Must have taken ages to get to 33000 feet. Perhaps chugalug with his Hastings experience can elucidate. Been to 35000 feet in a Herc on high level free fall trials. We had special oxy fit, and had to pre-oxygenate on the ground for an hour. It was very cold up there !