I hand mill soaps...but I do not sell soap, these are for my own luxury so I have the time. What I did was made my soap with a 2% SF then I grated it. I then let it sit for around 4 weeks. I then throw it in a crock pot, put some oils in to take it up to 5-8% SF, then I wait until it is melted some, then I add some water and powdered milk (around 1/2 cup water to 1/4 cup powdered milk per 2lb batch). At this point, I have to be careful because the heat of the crock pot will scorch the milk. Then when it is really melted, I use the whip part on my stick blender and beat it up thoroughly, when it is all melted together, I put the spices, mica's, FO, EO's in and pour into the mold.
Hand milling is like CP, you have to figure out what works for you. I have found this method works good for me. I use less FO, it stays longer in the soap and the skin, and the soap seems extra mild. HTH