I've been watching this thread with some interest (BTW, great stuff Dany51 and Viktor), and I thought I might pass along another idea which can be done with the custom picker which I've been doing for a while.
One of the things I've been missing with Artrage was a place to "smush", blend and mix the colours. Don't get me wrong -- the pre-set mixers have been good but when it comes to things like skin tones and eye colours I've found them a bit awkward to work with. So, I started saving 200x200 colour pickers where I've been premixing them and then saving them for previous use. For example, on a recent painting, I used the colour picker below to emulate skin colours.