As the owner of said C8 OTA, I can comment that "mirror flop" in an 8" SCT has not been a problem to me, but then I've only ever used it for visual work. The Celestron C8 can have a dovetail plate fitted, Bintel + Andrews sell them, which will fit into predrilled holes, and hence onto a EQ5/6 or Losmandy mounting...
And I will also add I'm only selling the OTA, there is no mount or tube rings on offer..
cheers
Mark