I saw a tip in a video about casting rocks. The author put the molds in a box of styrofoam peanuts to keep them level.
Of course I forgot this and as my hands were full of plaster I searched for a box to do this. I stumbled across a box with a hand full of peanuts and said "AH, forget it" to myself.
I continued my casting and noticed how much plaster I was using trying to fill these extra deep molds. Then it hit me, stick the peanuts into the wet plaster and the level would go up to fill the mold. I believe this will make them lighter, save plaster, and possibly make them easier to work with if the back side needs to be filed down later when mounting. I'll have to see if this works or leads to problems. Joe