Mike,
For the alternator you may need to go down to 7/16" width or perhaps even one fraction next smaller. I don't recall what that particular dimension was....
Otherwise, for AC belt and an Alt belt, here is where my expertise falls......as my car had the alternator mounted on what would normally be the smog pump wing of the bellhousing!!! SOOOOO, I must defer to the masses to follow up here!
TO make matters less fun, I checked my "alternator pictures" out from various cars, and found at least 3 different rear jackshaft pulleys in use!!!! 2 sheave and three sheave! I also wonder if I didn't see at some point in time, a belt running the AC pulley which then back fed on a second sheave to the alternator!!! Talk about "your mileage may vary!"
Since that part of my rebuild had already been figured out during prior engine swaps etc, there was no change in belts this time!
Cheers!
Steve