Let the individual layers solidify before pouring another layer or changing the angle. Here are a couple ways you can do that, but there may be others. With either of these it helps to bring your oil & lye mixture just to emulsion before splitting and adding fragrance and colorant to the batter comprising the individual layers. Then bring the individual layers to trace. If you take the full batter all the way to trace before the split, things will move quicker than you might prefer, especially for the latter layers, and especially if you've already added fragrance and colorant.
One - add an accelerating fragrance to an individual layer right before you pour it. You want to pour it when it is still fluid enough to settle on the level (or tilt), but then let it sit and harden before repeating that process for the next layer. It sounds easy but it does require conscious thought.
Two - after pouring each layer you can pop the mold in the freezer (or outside if it is cold enough) to make that layer solidify quicker. This technique also works best if you don't add all of your fragrance or colorant up front, since those can make the rest of your unpoured batter solidify too quickly even if they aren't big accelerators.
