How to set up palette is a very personal choice. One must ask several questions before squeezing out the precious (expensive)colors into the wells of the palette.
1. Do I use hard tablets or tube pigment?
2. Do I want intense colors?
3. Do I want to know mineral contents of pigments
4. How large a palette am I willing to lug around?
Once one answers these questions then decisions can be made. Above is a picture of how I lay out my colors. Intense colors are important to me so I decided to have separate wells for yellows and the same yellows that would be used to make greens. So I created extra wells for all the colors -one well is kept pristine the other is used when mixing.