Hi David,
As to point 1:
From the PDF manual, page 139: “Negative temperature compensation ratios indicate that your focuser will move INWARD as temperature drops.”
A positive temperature coefficient is observed when the shrinkage of the tube with dropping temperature is the main factor. Some (perhaps all?) refractors show the opposite behavior, because the refractive index of the glass in the objective exhibits a strong temperature dependence which often overcompensates the tube shrinking. If this is the case, an overall negative temperature coefficient results.
The temperature coefficient (with correct sign) is best determined by using Mikael’s SGP Auto Focus LogViewer, see SGP AutoFocus LogViewer . The download URL is SGP AutoFocus LogViewer download | SourceForge.net .
As to point 2:
From the PDF manual, page 49: “Reverse focuser direction: Reverses what is considered In and Out movements”.
This has to be adjusted correctly, but you have to do it only once for a given focuser. The adjustment of the correct focuser direction has to be made at first.
Please note that the adjustment of focuser backlash (PDF manual, pages 49 and 50) is critical for the correct operation of Auto focus and temperature compensation. In SGP, the backlash value needs not be accurate, it must be large enough.
Bernd