I used a C-11 for many years on a Losmandy HGM100 and later a G-11.
I had no problems getting perfectly round stars...though... I was using a self guiding CCD camera (and still do
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C-11's are a great 'scope and the Edge versions should have better "edge" correction....but at around 3 metres focal length I'd also suggest you will need to use an OAG, plus have either a quality mount or something well tamed at least.