IMO, that's a tough call. Inlet will be hottest, but you'll probably use the low speed fan more. To make sure you don't overheat when the A/C is on, put the high speed by the inlet as long as the low speed by the outlet is enough for driving in traffic when you don't have the A/C on.....tough call, so I see why you asked.

70 Roadrunner convt. street car 440+6, NOS, 4-spd, SS springs '96 Mustang GT convt. street car '04 4.6 SOHC, NOS, auto, lowered "Officer, that button is for short on-ramps"