Which color space would be best for lossless compression purposes ?

Hello,

Which color space would be best for lossless compression purposes ? and
why 
?

Compression techniques could be:

1. Runtime Length Encoding. (Good when many repeting colors next to each 
other)
2. Sliding Window Color Lookup with smaller index. (Good when many
repeting 
colors near each other)

Color space could be:

1. RGB,
2. R'G'B',
3. XYZ,
4. L*a*b*,
5. L*u*v*,
6. Y'PbPr,
7. Y'CbCr,
8. Y'IQ,
9. Y'UV

Bye,
  Skybuck.