I have been having some guiding problems in Dec with my AP900.  I used Pempo's backlash exerciser and the backlash compensation via the keypad and managed to get the Pempro graph looking good after adjusting backlash compensation to 5 (on a scale of 1 to 10).  Then the clouds rolled in and I won't be able to test guiding until I go back to my permanent setup next new moon.

I'm just seeking opinions as to the merits of backlash compensation versus trying a mechanical adjustment.
Geoff