Thank you for sharing your findings Adam. It looks like both correctors significantly decrease the FWHM across the field
I have found that in order to get reliable measurements with CCD Inspector, I must take a minimum of 15, ideally dithered images, and also calibrate them with a master bias, and then upload the images to CCD Inspector for analysis.
I know it usually is a pain, but it might also be worthwhile in a long term, if only for the peace of mind, to move the correctors 1mm closer and also 1mm further away to see if that improves stars shapes.
I have been contemplating a fast 10" Newtonian myself, so I will be looking forward to reading about the results of your investigations
