Those diffraction spikes do look ever so slightly double and thus out of focus to me
I have always just focused by eye looking at an enlarged star on the screen in real time (usually 1 or 2 sec exposures) and without any sort of mask. I just press the in and out buttons until the focus star is as small as possible
in reasonable or better seeing it is quite a quick and easy process however in periods of bad seeing it does waste some extra minutes as it is harder to tell if I truly have the very best focus due to the star going in and out of focus due to the seeing...especially with the tiny CFZ at F3.8.
Mike