Thanks for the comments Leon, Ken and Phil.
Upon further testing and analysis, my imaging train is producing an undesirable field curvature which is actually higher than I initially tested (around 24.7%). This is not an optical problem as one would normally expect. It’s caused by the X/Y tilt of the CCD camera. Having a large format 35mm chip, if the camera isn’t perfectly square on the optical axis, any camera tilt will be seen on the edges. The tilt throws all the other numbers out such as collimation etc.
I've ordered a custom-made M92 male to M92 female focus extension adapter from
Precise Parts in the US which will significantly strengthen the camera mounting. I intend to still use the scope as I can remedy the curvature in processing, be it is less than optimal. Prevention is better than a cure.
Attached are one of the field curvature tests performed. Actually, these were 10 minutes lumance exposures. When performing the optical tests, they should be no more than 15 seconds exposures. Regardless - the curvature is present either way. I will be certain to post the new results once the custom-made adapter arrives. Curvature should be around 8% for the FSQ (not 24.7%!)