I use 'roo almost exclusively now.
I cut the strings, soap and stretch. Then I bevel. As I'm braiding, I will soap again, as needed to seat the strings properly.
I use a recipe I found in one of the whipmaking or braiding books. A pound of lard, a bar of Ivory soap, some water. Cook it up and don't let it boil over. Makes enough soap to fill a 2 lb coffee can.
If I'm braiding horse tack or anything that's gonna be hanging outside, I add a couple of drops of kerosene. This is supposed to keep bugs out of the leather.