I've come around to this way of thinking after carving a few larger wall pieces and an octagon corner.
What are needed are slabs in half inch and quarter inch thicknesses. These thicknesses would link in to the HA full size and small block, Linka double thickness wall and the Terrastone blocks.
The mould surface should be very faintly marked with a quarter inch grid to make cutting to size easy. The overall thickness would be greater than the stated size to allow for sanding etc. and the grid would be easily removed. I for one would carve on the blank side anyway and only use the grid for cutting to size.
The size should be a minimum of 4" x 3" larger if possible.
Casts could be supplied through the CMP, but I believe that the moulds would be a big hit as well. Casting blanks in the plaster or wax or whatever the sculptor uses would be a great help for those of us who use different media for different subjects.
Anyone else want to chip in their comments .............. PLEASE?
All the best,