In grey scale terms red is middle grey and for that matter so is blue and green, throw all those together and you have a greyscale of less than one stop, which is BORING BLACK/WHite.
Understanding luminosity is very important with converting.
FInd a copy of Vincent Versace "Return to Oz" he discuses practically every know way to convert to black and white
Shooting in jpeg and RAW at the same time can be very helpful in learning to "see in greyscale" use mono for the jpeg, and the RAW will be in color, you can then convert the RAW file in a variety of ways, using the jpeg to review the scene to help understand how colors relate to each other on the greyscale.