Dude it's amazing ... Nice proyect and thanks for share all those pics, comments and story
I have one comment in your build up .. and a side note I never dealing with cummins engines.
But .. in Toy engines in 60 series, 2H and 12H-T the temp issue is important coz you haven't really much flow rate coz the 60 haven't a wide front grill to allow it ..
So if you gonna palce the intercooler in front I thought you don't gonna have enought room to grill+intercooler+AC condenser + rad .. ( forget tranny cooler )
IMOP you can run without grill intercooler + AC stuff and rad .. and place the tranny cooler in other side .. with a electric fan.