I first carved the heart and built up the thorns on top with a heated wax pen. I planned for the stones by cutting the seats, but I did not drill all the way through. I believe there is a greater chance of casting failure if you drill the “breather” cleaning holes behind the stones in the wax model. The “stalagmites” of plaster in the plaster mold can get blown down by the molten metal entering the mold causing huge pits and voids in the ring.
I drill them out before stone setting.