The big problem on 30mm is not to mud the colours its so easy to mud 2 colours next to each other. That's why on 30mm I let one colour dry first. That's usually the lighter first, then add the dark so if you go over the light colour, you can wash it of it with out muddying up the lighter colour. Just thought this might help you Rodger with 30mm. Slows down painting time but stops the chance of muddying.
Chris