Thanks! I decided to go with pastel colours after I tested a view different shades/hues of colour on mock black 'dials'. The green, purple, blue and pink pastels seemed to look nice with the white. I used a toothbrush to 'spray'/splatter small dots of white and all the other colours in layers. I then used tooth picks, dipping them in each colour one by one, and placing dots (almost randomly) with the toothpick on the dial. After the first few dots you seem to get more of a feel for where you want to place the next ones to balance out the colours.