couple of thoughts: you want the IAT to be at the core of the airstream for best accuracy. ideally, it would be in the plenum, right after the TB, but that would be one hell of a time getting setup, so i would be looking to put it in the charge pipe right in front of the TB.
you CAN run the booster off of a smaller port and it won't effect operation too much(so long as you don't need to pump the brakes rapidly). it'* actually an old trick to keep the booster from messing with the MAP signal too much when it operates by inserting a restrictor into it'* vacuum line.
1995 Monte Carlo LS
3100, 4T60E, OBD1 Conversion...for now, future plans include a 3900, T04E-46 (Knock-Off) turbo, and a F40.