It appears that I had my terminoly wrong. I am aiming for the Zero Pressure setup:

""The ZERO PRESSURE tank will recover the expanded coolant as it increases in pressure. Once the pressure exceeds 15 PSI the big spring on the radiator cap will be overcome by the pressure and allow some small amounts of coolant to dump to the ZERO PRESSURE tank. Later, when the coolant cools off inside the engine it will create a vacuum as the coolant changes to its normal unexpanded size. A small vent in the radiator cap will now open and draw the coolant back into the radiator so the cycle can start over again in the next driving event""

Thanks for the reply.