... I would use this site

http://www.csgnetwork.com/csgcolorsel4.html

to get the PWM data of R G B:

Set S=100, V=100 and run "H" from 0 to 360 in equal steps.

To gain more colours than only the full saturated ones he can repeat this procedure with S=75, S=50 and S=25 (keeping V=100). This will give him also some very nice pastel colours.

Now he has a raw PWM data set for R G B to generate very nice colours.

To make things perfect he can finally fine tune the intensities of all colours by trial and error in his final setup by multiplying the R G B values of a too intense colour by a suited factor (e.g. 0.98), which corresponds to a decreasing of "V" value in the above colour converter.

The above colour converter demonstrates, though, that he will need the whole range of 0...255 in his PWM drivers to accomplish this.

Kai Klaas