Get Powerstrip and install the 24p settings that are predefined in the Powerstrip settings. The HC7000 has no problems with 24p processing from an HTPC (have three of them running with the HC7000).
It depends what your graphics card produces. If it does 0.255 greyscale, you have to set the HC7000 to enhanced. Standard otherwise.
All questions esp. the last one should be answered by the person who did the calibration for you (you paid him/her, didn't you?).
Why don't you ask your dealer?