The trouble with inlet temp is it will vary greatly with ambient.
The other thing about inlet air is, the warmer it is the more efficient at low power output. Cooling the inlet air increases performance and fuel consumption.
The coolant, on the other hand has a thermostat on it. The goal is to use the minimum amount of air for a given condition and keep from running the cooling fans. I have a 190 thermostat in there already which works great under load. The old cummins 'stat would cycle terribly, it would get to temp, open too much, cool way down, repeat.
The new one has the temp rock solid when towing.
Driving around empty, the boost is almost non-existent. I really do not need an intercooler at all when driving for good mileage empty. I never exceed 5 PSI if I tenderfoot it. Remember I have a mechanical pump with no electronics whatsoever. It just delivers fuel to the engine according to my foot. Nothing more or less.
So now I have a solid 190 on the gauge, I'll set my cooling fans close at 195. I'll play with that for quite a while.
Then I'll close the louvers with an electromechanical servo. I'll figure out a way to get me a position indicator.
The linkage will have a slot in it, and a simple air cylinder hooked to boost. The electric system will set the standard cooling and is what would get computer automated.
The boost system would get balanced against simple spring forces, possibly a needle valve for rate input. Any time the boost comes in I want intercooling right now. The air cylinder will provide that. When the boost event is over (pulling a hill with trailer, etc) it will let go back to whatever the electric servo is set to.
Who knows, I may have the louvers substantially open when towing anyway? No way to know till I get it installed.