Not directly from M100 whilst digitising/acquiring. Only from Beta machine that has adjustable TBC. You can of course monitor the video levels & chroma saturation incoming on the M100's waveform monitor & vectorscope.
If you can't adjust the black levels from the machine at that time, you can do so in the colour corrector during the edit.
Actually, Brian was able to do what he was looking for. He and I were on the phone yesterday (they have a Support contract) and we were able to tailor the Video Input/Output Preferences to suit his particular source video. It boiled down to a combination of the SMPTE vs. Beta setting for Component Video for the Input and the IRE setting for the Output.