Looks good. In regards to starting colors, I find these RGB values come pretty close to the "natural" tricolor:
Non-specular Sea Blue: 11, 31, 38
Intermediate Blue: 111, 124, 138
Insignia White: 255, 253, 250
However keep in mind both blues tend to become grayer as they fade, and aircraft in the PTO tended to be HEAVILY faded. I've seen some photos where the darker top surfaces and the intermediate blue flanks are so faded that they're nearly blended together.