I mixed it into the lye after I dissolved the lye in water. Gotta adjust water-carrot ratio based on what you want for total liquids. And if you're going to add milk also, gotta account for that in the total liquids, even if you put it in the oils instead of the lye. Hard to say exactly because a lot depends on he other ingredients and some depends on whether you are going to HP or CP. Some people put it in at trace but use less. I used 8oz and also I did HP. I can put my whole recipe-instructions but it's very long lol.
Basically mine went like this -- mix lye into water. Add carrots. Mix milk into oils and melt in crockpot. Add lye-carrots. Mix mix mix to trace. Cook. Don't let it boil over. Mix mix mix. Don't let the carrots separate. Almost done. Add honey, don't let it overheat. Mix mix. Cook till it passes zap. Cool a bit. Add scents. Mix mix. Pour. Cool. Yay!