I never EQ the master bus, recently my master bus usually looks like this:
ozone maximizer (loudness)>oxford inflater with the clipping off (for filling in harmonics very slightly)>camel phat with everything off (to bring it back to 0)>oxford limiter (for a bit of extra loudness + slightly filling in harmonics again and limiting obviously)
You don't EQ it at all?, correct me if I'm mistaken but from what I've learned it is better to EQ in the master because you can get rid of frequencies that are below 20Hz and maybe to adjust the high end a little bit, or you could just have an incredible mix.
Also, the harmonic filling process that you are talking about its like saturation/colouring? or they are different things?, sometimes terminology isn't very friendly to be honest