Wrap of athletic tape at 20" and 24". If it's under 15", shake them off the hook. Haven't cracked the 24" mark in a while though. Might just remove it and if one measures over 20", it's length is just "big".
Is anyone measuring 3" - 9" range? You should be able to eyeball 12-15" and that's close enough unless it's something for a record book.