No need to be exact though that does allow for a prettier jig, SB etc. I use different brush sizes to help. Bigger for larger amounts of powder, thinner for smaller dabs of powder. I heat the jig and apply the base coat, then dab the top coat on the top and some on the side. Sometimes I have to reheat to set the powder. If I want a third color, I touch the bottom into a powder I have poured onto a paper plate, go straight to the heat gun, then bake. Not sure I have seen a symmetrical looking shad, craw fish or frog in the wild so coloring outside th lines works for me in spite of what the teacher told me.