Transparency/Opacity when Choosing a Palette No.77

Some oil pigments are by their nature more transparent than others. Discussion is of whether or how much that should be the basis of a decision of whether on not to include a color for your palette when painting in a full color range for example as Paul does

QUESTIONS: I've been thinking of expanding my own palette from brown/blue to colour and wanted to ask if you have some advice regarding the opacity of paint. To be more specific: should the pigments used in a palette be of the same opacity/transparency to make the wet into wet blending more manageable?PEIK