Fixed
The RGB filters actually vary from pony to pony, like for example, (this is taken from the official Flash game) front coloring to back coloring for Fluttershy is
.5R+118
.5G+106
.5B+50
For Twilight it would be
.61R+47
.61G+35
.61B+54
I think there might be one, consistent for all HSL filter but these are official RGB filters from Hasbro, so, yeah