I would do as you say ther largest intercooler with a alloy rad, but also put in a swirl pot, and plumb this to the expansion tank via the TOP smaller pipe to act as a degas, as cooked water forms air.
Look at blockin in the air flow of the radiator, so you get no side spill of air, as air will take the eaisest route, it will go around a object(radiator) if it is easier.
Fit some bonnet vents.
tabetha