>>>>When it's this close I'm not going to argue an inch or so.
Neither am I, I just felt I should point it out it can be wrong to a degree
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>>>>Sometimes, even with SerpWidget, if the snake is in a strange curl, you can easily add or lose 1-2" as well.
I found that it's better if the snake is laying flat. If it's lifting it's head or coiled over top of itself, you will always lose length, simply by the way the program works. Depending how you follow the snakes curls, you can add or subtract more length.
>>>>>But I think it's the best thing for basic measurements...accurate enough and easy to use, plus we can all check each others out in case someone has some wild claim and most of us would come up with a really close match with each other
Agreed...I didn't post to question anybodies lengths, simply to point out that they will be close proximities rather than precise measurements. I use it all the time, and wouldn't give it up for the world. 
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Ace