Hi Paul,
I regularly used a Meade 0.63 focal reducer on the CGEM1100 with great results.
Admittedly it was an EQ mount so I had no clearance issues to be worried about, and I had zero problems achieving focus.
I also ran an SCT micro focuser in the image train and a 2" diagonal. My go-to eyepiece at the time was a 24mm Panoptic, but I also regularly used Type VI Naglers, Baader Hyperions, an ES 14mm 82deg, as well as 26mm & 32mm GSO Wide Views ..... all successfully through the focal reducer.
With this configuration I can recall some spectacular views of Eta Carina that have been engrained in my memory forever
Paul