After further research I have decided to get CentralDS to install the Astronomik MC clear cover glass after they do the sensor debayering. The debayering process yields a highly reflective sensor surface and the original Canon sensor coverglass is too reflective - resulting in bouncing light (apparently). This utube video explains it better than I can:
https://www.youtube.com/watch?v=pwYmmNtGTqg
This is not an issue if your leaving the bayer matrix alone (OSC) but for Mono conversions it should be considered. The alternative might be to run an Astronomik Clear Clip-In, or even a Baader Clear or UV/IR screw-on filter on the front of the T-adaptor, but having it down just above the sensor provides a sealed chamber and protective surface above the sensor face (that's my logic anyway). And of course the Anti-Alysing (Low Pass 1) is no longer required.