I'm using illustrator, with global colours.

I've tried a green (positive)-amber-red spread of colours, and the argument from the editor is that the red is more 'eye-catching' and therefore looks more positive.
I tried a red-grey-black spread (red being positive) but he thought that looked dull and lifeless.

I'll try the orange-blue spread and see if that garners a more positive (sic) result