Funny you should post that. Just today I asked Jeremy about how best to measure oneself in current for the purpose of performing navigational squares etc. (I'm retired and think up lots of goofy questions in my down time.) Since I figured current would mess up nearly everything! His answer was a review of my AOW which I took years ago. Arm spans were what we came up with. Everything else (outside of a tethered line) was FUBAR.