What I did was melt all of my oils and FO's together. Then I made my lye mix and separated it into 4 separate containers. I started with the black and weighed 12.5 oz of oil, (my batch was 50oz total oils) added 1 of the lye/water mix,1 tsp of Charcoal and brought to trace. After pouring into the mold, I set it in a warm oven for about 10-15 minutes. One I could feel that the top was set. I'd mix the next 1/4 but adding TD instead of Charcoal. I made sure to pour over a spoon just in case the first layer was still soft. Repeat 2 more times then wrapped in blankets to gel.
Sorry if that was WAY too much info haha! I love talking soap ☺ this morning my daughter called me a soap hermit.