[fritchie]

Thanks. The point I was missing is the flat original. The similar procedures I've used and seen here are for final waxes with a twist of some sort to the pose. In those cases, a flat bed of some sort of clay is built up under the original, a barrier for the plaster put around it, and from there the process is similar to yours. This generally takes me about two (interrupted) days, but the shop I mentioned does it in one working day, with shorter pauses.