You don’t need to download the focus frames and evaluate data from (currently not existing) FITS headers of focus frames. The data you are looking for are in the SGP logfiles and there is a possibility that is much more comfortable:
SGP user mikaelA has made a very useful utility for the evaluation of SGP logfiles for this purpose: SGP AutoFocus Viewer: see SGP AutoFocus LogViewer and SGP AF Logviewer v1.2 Release. It is intended e.g. for calculating the correlation coefficient that is needed for applying focuser temperature compensation.
The download website is here: SGP AutoFocus LogViewer download | SourceForge.net . The current version is v1.24.
Bernd