I let the first color soak with no vacuum then cook it off. Then I either do the same thing again with another color or go ahead and pull in the final color with vacuum and then the final cooking. Changing up the way you place the wood in the dyed stabilizing juice can make interesting colors. Put a piece on it's end in one color, let it soak as much as it can. Flip it over in another color the same way let it soak all it can then cook it off. Do the final submerged in a different color then do the final cook off. Lot's of ways, orientations, and color variations. Just remember the final needs to be under vacuum to pull in the most solution and give that wood it's hardness.
Wayne