FED,
You say that there are no age limits in China, but I don't think that's strictly true. I know there are a number of over 60s working in southern China, but I was offered a job flying in northern China and the offer was withdrawn because the northern department of CAAC wouldn't issue a medical certificate to anyone over 60. I'd already been told about the tests to which you referred, but they wouldn't even allow me to sit a medical.