"Am I warm or cool and WTF does the colour wheel do anyway?"

To understand custom colour blending, it is essential to first understand the underlying principals of mixing pigments.

Primary Colours

Primary colours are colours that can not be created by mixing other colours together. In essence, they are the core colours when mixing pigments.
The primary colours are:

• Red
• Yellow
• Blue

Secondary Colours

Secondary colours are those colours created by mixing 2 primary colours together.

• Orange (Red + Yellow)
• Green (Yellow + Blue)
• Violet (Blue + Red)

Tertiary Colours

Tertiary colours are those colours that are made up by mixing 1 primary colour and 1 secondary colour.

• Red Orange
• Yellow Orange
• Yellow Green
• Blue Green
• Blue Violet
• Red Violet

You could go on - but why beat the coloured horse any harder than we already have?