Find an existing recipe on Glazy.com and modify the color. Mix up 1000 grams of the recipe, omitting the colorant or colorants, and substitute one or more colorants to change it to a new one. This can be either at Cone 10 or Cone 6, or at Cone 04.
Mix up the recipe as written before modification and apply to one pot. Then make the modification and apply to another pot. You may have to make a line blend of the new colorant to find the right amount.