A Stone's Throw Away from Insanity

Augh, I'm tired.  But I guess I'll let you in on my random thought of the day.  I was thinking, we always say something is a stone's throw away.  How far is a stone's throw?  How far can you throw a stone?  Maybe we could average our stone-throwing distances and round it off to a nice even number, and call that a stone's throw.  Then when someone said, "That rock hyrax isn't even a stone's throw away," you could whip out your measuring tape and (assuming the little critter doesn't run away) say, "Nuh-uh.  That rock hyrax is precisely 154 feet, 4 3/16 inches away.  A stone's throw is only 150 feet."  Your companion would probably look at you strangely and then slowly back away, but at least you would have the satisfaction of knowing you defined a previously nebulous distance.
     Like I said, I'm tired.  And my thoughts are pretty strange.  But at least it's a post, right?  Hmm.  I need more sleep.  Goodnight,
Randy