There are three things that need to be taken into consideration when designing a cooling circuit and Woody, you should know this like I know this car...

1) You need to have the ability to evacuate the incoming medium (coolant or water) at a rate of 1+:1. This is why you have small registers and large returns. You have a pump (fan) that pushes air through your home but said fan also has to push said air back to the exchanger or distributor.

2) You need to have adequate flow. It doesn't matter how cold you get the medium you're using to remove the heat if you don't move it through the circuit as quickly as you can. With these cars, there is no limit to the amount you can move through without reaching saturation unless it's 100+ gal/min, it's saturated before it gets to the outlet. More powerful pump, move more fluid, remove more heat.

3) You need a way to remove the heat from the saturated medium. Like an air conditioner, unless you can get the medium cool again, the next time it passe through the cooling circuit, it will become saturated sooner. Increase the size of the heat exchanger, you add more surface area for the cooler air to cool the heat saturated medium. If you add a reservoir to the circuit, you can most times completely mitigate this due to the increase in volume and the ability to increase the cooling capacity of the circuit by changing out the water or by the addition of ice.

That being said, a single-pass or triple-pass intercooler will only work as well as the rest of the cooling system it's part of. If your only upgrade is a heat exchanger, you should stay with the triple-pass IC because you aren't moving enough volume. If you have a high-flow pump and a larger heat exchanger, a single-pass IC will only show slight gains but shouldn't be overlooked due to the fact any gain in cooling and resultant lower intake air-charge temp translates into more power. This is one of those bang-for-buck decisions. If you have a large heat exchanger, a high-flow pump and a 3-4 gallon reservoir, a single-pass intercooler will really impress and with the addition of ice, can actually yield charge-air temps lower than ambient!

Take care