Not sure quite yet, these (along with the other busts I am about to start molding) will be the first time I mold my own stuff. I am trying to keep the cost down, which is why I am doing it myself instead of sending it to the molder/caster. I'll let you know when I can, if you'd like.
I think my biggest issue was with the silicone I got; it refused to cure, and I tried several times, accounting for temperature, humidity, exact mix ratio, etc. It was cheap "mystery silicone", so for the next attempt I'm going to buy something name brand. Probably Dragon Skin, I've heard a lot of good things about it.
Yeah the thing I found works best is a 50/50 mix of 99% alchohol and isopropyl myristate. The alchohol dulls it down a little, if you just use the Iso M it will kind of melt the clay down, making it VERY soft. It will dull down the details if overused...use it sparingly!