I have tried and failed for the 3rd time, but I think I have finally hit on the solution (if you don't mind me making a suggestion since I am one mistake ahead of you). I think the solution is to make one batch of soap with just the white, pour at thin trace so the top is nice and level, and let it sit up AT LEAST 6 hours, then make a 2nd batch with the swirl, and pour it on top. I think this will keep that second batch from breaking through the bottom layer. I also figured out that that has to be the secret to ombre, as no other solution I have tried has worked. And I have tried and tried. Thin trace, and let the previous layers set up. If I get the errands done and the house cleaned, I am going to try this this afternoon, so I will let you know.