Re: What color to burst?
Well, the most obvious answer is 'the colours you like most'.
In fact its really the only answer. Have a look at a lot of guitars and see what you like and the method used to get that effect, and then check out vidoes of people doing bursts with your chosen method. Its really the only way.
The key if you haven't done finishing before is to practice on scrap wood of the same type of colour or porosity.....regardless of whether you are staining wood or mixing the dye into clear for the colour. A burst requires feathering of the outer to the inner, and then there are sandback techniques for the flame enhancment route.