Seasonal pitch change:

[RicB]

Anyone wanting a little tool to look at how much change in string length 
for various parameters can just download this little toy of a 
spreadsheet that lets you input bridge width, offset angle, and pin 
angle and yeilds the increase in string length across the bridge 
surface... amoung other things.  Enjoy

http://www.pianostemmer.no/files/String_displacment.xls


Cheers
RicB