Long in the tooth??
I am 6' 3"....I am a 33" leg......so I am long in the backbone. I was on F3s when we went through a phase of measuring us lanky back seat types after a recent BOI. The rigorous testing involved sitting in the back seat (where I had been flying for some time anyway) and the Doc using some high tech equipment ( a cardboard tube!!) to check the gap between knee and panel. Being long in the back I passed this test easily, 2 others failed (experienced F3 chaps). One went to multis and the other pulled rank and remained.
Eventually ended up on AWACS where a long backbone was handy when reaching into the freezer cabinets for a frozen curry!!
Its all in the dimensions