Restricting the mouth of the coolant nozzle will up the pressure and less volume will flow, with the result of more consistency and increased effectiveness. Realized this after some aluminum chips partially blocked the nozzle.
Also, aiming the mouth so it's spraying towards the drain, and not away from it (ie from left to right, and not the more natural right to left), speeds up draining and lessens starvation at the pump.
Still, the pump is a weakpoint. I'm thinking of getting a cheap cdedicated ompressor and hooking up a mist system with venturii vacuum in place of a pump.