MP <-> CO workflow for variants ; cc pls

Now that MP1 1.1 and CO 6.3.2 are working pretty well for me (as long as I am patient with MP), I have been trying out a workflow to catalog CO variants. I am looking for your thoughts, or how you handle it. I choose to keep the master raw images in color in MP.

Most of the variants that I want to catalog separately are black and whites images converted from color.
I am trying to use the color labels that exist in both CO and MP. Unfortunately there is not a 1 to 1 mapping for all of them.

The color label scheme I have in MP is shown here
http://www.pbase.com/jimmsp/image/139497338
http://www.pbase.com/jimmsp/image/139497338

I have chosen to label a image in CO that I produce a B&W from in a variant as pink in CO. That then comes across just fine in MP when I send the file from CO to MP.
If I output a B&W file from CO, I give that B&W image a grey color label in MP. That grey is not recognized by CO.
This seems to work for me, as I have also B&W images generated in PS and Lightroom and Topaz which I can also give the grey label to.
Finding the grey label then allows me to quickly call up all my B&W images.
Finding the pink label allows me to get the original color raw file where I can open it up again in CO for additional processing.

I could use the orange label for another style of variant if I choose to, but I don't as yet have a consistent need. I envision giving it to an output file that has been modified in a variant (such as no noise reduction, or no sharpening, ..) that will processed further in another package.

This scheme seems to work, but might be too complicated.
All comments will be appreciated.
I'd also like to hear how you might track B&W images and variants in CO.