JTIDS,
"The docs know what fits".
After some additions to the Chinook cockpit the doc had to sign each if us off as being able to fit in amongst the new equipment. The conversation went something like
Doc. Can you reach all the switches?
Me. (After brief consideration of whether I still wanted to be in a job or not)
Yes
Doc signs off a piece of paper for my logbook and the next candidate steps forward.