They quote a 70mm image circle then only show vignetting and spot diagrams for a 42mm circle
It will need a compact camera anyway.
Back focus is going to be very limited. Shame they don't give us the data in the specs. I doubt it will be possible to fit an OAG but at 620mm focal length a guide scope will be fine if the mirror doesn't slop around.
Will be interesting to see how the results compare to a Hyperstar set up.
Cheers,
Rick.