I have been making molds for 30 years. when it comes to a ultra cal mold or plaster mold "ZERO" release agent is needed. Infact....if you use mold release with latex and ultra cal, the mask will take longer to dry and will not be as thick as it should be. As far as higher quality with a realease ....false....

Heres a good one- I use release on my latex mold that makes latex masks....
Did I just say that? Thats right...do it all the time...

darksidestew