When I did a flight from KSEA to PHNL with version 1.0, I used step climbs throughout the flight. I didn't have any info to go by, so I went by "feel" (I can't think of any other term to use). As the aircraft got lighter I was able to climb higher. I have managed to get to FL410 on one flight I did, but she was light to begin with on a very short hop.

I found some interesting this info HERE. The 367-80 Prototype (1954) had a Service Ceiling of 43,000 feet and the Advanced 707-320B had a Service Ceiling of 36,000 feet. Ishall now take it that FL360 is the Maximum Altitude.

Mark