I\'ve used 2nd method before - I think it\'s called tweaking. Just place the 2 colours next to each other on the mini, create a mix of the 2 and in very very thin layers, slowly build the transition.
Did it just the other day. You gotta be quick. Put both colors down or their respective sides, quickly clean your brush and lightly scrub back and forth on the border mixing the two. Takes some practice but it can be a snap with a little work.