Steve, I obviously misundersttod your original posts... I thought you were going to isolate the charge air cooling system from the engine cooling system by adding the new tank to be for IC coolant only... Forgive my poor reading comprehension

Now that I understand your thoughts, I think adding an extra coolant tank for the engine is not necessary... The ECT's (engine coolant temps) never really get that high unless you are sitting at idle in rush hour traffic with your air conditioning on during a hot summer day...
What needs to be cooled more is the charge air coolant that runs thru the intercooler to reduce your IAT's (air intake temps), that will help increase engine performance (HP).
I hope this answers your question as well... The intercooler has coolant flowing thru it to reduce the IAT since the compression from the SC heats the intake air more. The charge air cooling system shares coolant with the engine cooling system via the overflow tank. But the engine cooling system really never circulates it's coolant back into the overflow tank, unless it reaches a boiling point (which is higher than normal water in a pot because of the ethylene glycol that is under pressure in the system raises the boiling point) and then it spits out the boiling coolant and steam from the radiator into the overflow tank.
All of my research has shown that the IC coolant temps only run about 15 degrees lower than the ECT's. This is robbing power... So if you can reduce the coolant temps running thru the IC, it will deliver denser intake air and you can increase engine performance (HP). That is why I thought we were discussing seperate cooling systems for the engine and IC.