Hi James--
Once you have your data (temp vs position), then run a regression analysis in say Excel which wil provide the slope coefficient and goodness of fit r^2.

I run FocusMax Temperature Compensation Wizard and collect a least 2 nights of data and compare the slope coefficients - I *DO NOT* combine the data from multiple nights to avoid introducing data bias (perhaps due to environmental influences). For my system, the slopes are the same on different nights but the regression lines are physically offset - see FocusMax Help/ Tips/Temperature compensation for more. FocusMax V4 will provide the data analysis from the data collection when the TC Wizard is run.
Keep us posted on your progress!

Steve Brady