Even better than a common white balance would be to bring along a gray scale chart or better yet add a McBeth chart to the shoot. Roll off some of the chart at the beginning of a scene and record it on all of your cameras under the same lighting conditions. After wards, in grading you have the same reference on all cameras and make matching much easier. Match each camera to your “reference” camera and save the color correction settings for each camera. When editing, you can just grab the CC preset you saved and apply it to the appropriate camera in the time line. You could also put each different camera on it’s own track in your timeline and simply apply the same preset to all of the clips on that track for a very fast rough grade of each camera in the edited sequence. If you are doing color grading outside of the editing software, just collapse the timeline and export to the grading program.
Fast and pretty painless. Just take the time to shoot the charts to begin with and it will save you a lot time later.
Tom
E=MC2+/-2db