> Would it work to put one or two layers on, then break it loose from the
> mold, then lay it back into the mold to put on more layers and/or
> reinforcements?

That would work too, but you would have to wash off the amine blush and perhaps sand a little before applying the final layers. I wouldn't try any less than 3 layers before removing it from mold. You don't want to accidentally bend the seat too much when removing it from the mold and crease it.

I ended up having to do a little bit of reenforcement after the seat was removed from the mold. After it had cured a whole day, I pushed down on the seat an noted where it flexed the most. I then washed and sanded the underside and put another layer in that area.