[jgmick]

I'm kind of committed to the sanding op after molding. There is going to be a lot of stuff that will need to be added/filled in addition to the material finish. (I agree, it sucks.) but I need to fill/prep it for paint. Thicker wall doesn't hurt. There is space available for quite a bit of material. I was planning on adding some ribs on the inside for stiffness anyway.

As far as pulling it out of the mold, all of the internal corners are filleted in the mold and the edges/corners of the mold can be removed individually so I think I'll be OK with that.
(No such thing as too much wax on the mold.)

How well can you add additional material to a cured part? I assume scuffing it up with coarse paper to break the sheen will work. Any surprises there?

I think I'll get some and just try it out on some scrap stuff and learn to work with it.