There are as many ways to do this as their are gunstockers. There is no best way. Bringing out the curl and achieving a particular color and finish are all intertwined. If you could bring out the curl with a purple or green dye and it would show the best, that would not be much help.
Spirit dyes and water soluble dyes are easy to control. Aquafortis and heat was quite a common method on originals and every piece of curly reacts differently. Many makers now use both- AQF plus spirit dyes to modify the results.
Sunbleaching the stock seems to help bring out curl. After getting the stock smooth as you want and raising the grain several times, take it outside on a hot sunny day and flip it over a few times. Then stain it darker than you want, whatever method you use. Rubbing the stock later will lighten it.