This photo is of the two batts that I made using a very plain slump mold made of clay covered with a sheet of plastic and some clay sides. The mold only lasted a few minutes but two batches of plaster were just right to make the batts I needed. The most important aspect of the batts is that they are concave so any really runny clay doesn't end up running all over while you are spreading it.
One pailful of the settled old throwing water (skimmed of clean water a few times) with the dry trimmings mixed in and let to soak, is the perfect amount for these two batts. I leave the clay out overnight in the rainy season as the plaster can only absorb water to a maximum and then lift the clay off the next morning. It sits in the damp cupboard overnight with the day's thrown pots. During the summer it is very dry here and a really dry plaster batt can pull the water out of the reclaim in about half an hour.
Just make sure the those plaster batts are NOT TOUCHING anything organic like wood, canvas, or any surface that could absorb water because this underside is a great way to rot things quickly. I pressed little clay feet into the wet plaster and it worked really well. Also, a nice place to dry the batts is around (but not on top of ) your kiln while it fires, or at the mouth of the exhaust fan if you are using one.