I plan on using Steve's "Vivid RGB" custom preset, but with respect to White Balance, should I take a white balance with the CP Vivd RGB turned off? Or turned on during the calibrating of the white balance?

Thanks

Hi,

I think it should be switched 'on' and then you should take a white ballance.
White ballance is set so the mix of the colors at maximum is mixed to white. That point can only be set right when using the preset you plan to use.
Everything else beneath white (all other colors) are made (mixed) with that preset (or any other).

Succes!