what you can do to home in on the parameters for the Sesto, is to work with the Sesto Senso Focus Manager software. Connect the focuser in the software, choose a setting and run the focuser out and in a few times. After a few times, set the focuser to position 0 and have a look at the physical position of your focuser tube…
If your settings are to aggressive for focuser, your tube might not be physically at the 0 position although the software thinks it is… Play around with the settings until the software 0 equals the physical 0 position.
The next thing I did was to use the SGP focusing, on a clear night, to home into the best focus I can get and then start the Autoofocus function and watch the resulting graph. Adjust the number of steps, I’ve found 7 or 9 to be usefull and the step size and then rerun the autofcus… My experience has been, that if the grapgh shows a “dog ear” on the left side, then my step size is too big. The step size and the number of steps should be large enough for the focus to change noticably, but not so large that the stars go totally out of focus.
If you’re still having issues after this, I would suggest you link the log file, so that more knowledgeable members can have a look at that, to see what’s going on.
Best of luck and CS,