Hey Steve,
From my experience and thanks to Brian's help I have learned that you shouldn't worry about DEC backlash measurement.
It is just a thing PHD2 can't handle with a spring loaded version. Besides latest version of PHD2 will measure and compensate it while guiding, the more you guide the better it gets.
Also the better your polar alignment and seeing conditions are, the less it has to correct DEC.
Your RMS error looks good!
Cheers,
Carl
