Im glad I read this thread. I just installed CCD inspector and it returned this result with the 10 inch F5,6 scope. I had earlier collimated is using a standard laser collimator, first aligning secondary by putting laserspot onto centre spot on primary, then adjusting primary to get spot centred back at its source. Though the scope has a full thickness pyrex Sutching mirror, the tube is only thinnish gauge sheetmetal, and the cell is only a simple 3 point one, but the collimation still seems okay.
I used a 10 minute sub from my He2-72 image, taken with the modded 350D, as the test image. (baader MPCC coma corrector fitted)
FWHM around 3 arc secs, not bad for hand guiding on a mount with a plastic RA gear wheel
I am keen to try CCD inspector with my 6 inch F3.6 SN, it I suspect will be very finnicky due to fast focal ratio.
yes I thoroughly recommend centrespotting the primary mirror. Collimation errors with the secondary show up instantly with a laser collimator and the centrespot.
I also turn the laser collimator in the focusser, to make sure the laser is exactly parralell to the focuser axis. Mine wasnt and so i had to "collimate the collimator" till it was. When turning the collimator the laserspot should remain stationary.