Put a option for settling the mirror prior to taking autofocus exposure.
At least with my system it takes about 10 seconds for the mirror to settle into a new position. I’d likely get much more accurate focus if there was a way to wait until you take the exposure.
Average a number of exposures for a given point on the V curve
Acquire the V curve data just a little differently.
Collect the right hand points as before to generate a linear regression line for that side. When the curve begins to tail out at the bottom move the focuser to the the extreme left-hand position and move down the V curve on the left. The advantage of this is that by the time you have identified a good focus position you’d be near focus. This would eliminate the large (problematic) movement of the focuser at the end of the current autofocus regime.
As it stands right now I’ve spent more than 40 hours of sky time trying in vain to get autofocus to work with my SCT. When I implement the above recommendations manually I can nail focus repeatedly. Thanks for all your work!!!