Monochome workflows are a great standard for doing channel difference based operations (e.g. removing tracking markers)
Monochrome Plus provides a couple of extra features to make the workflow faster.
Features:
Weight - controls each channel's contribution to the final monochromatic channel
Source/Target - allows the user to divide/multiply the monochromatic channel.
Use weighted target as source - replaces the source values with a weighted multiply to allow colour matching with one colour pick.