thought we were talking charging Im sure most pullies are different,but mine(march) dont have any over heating problems at idle,only when I do 2500rpm,or better on the highway.
I have a 94 GT with UD pulleys (not sure which brand), and my headlights dim at idle, especially when I have my subs on. I've never had any problems with it tho, cuz as soon as I get above 1k rpm the voltage jumps right back up.
I recently have been running a bit warmer than before, but I think thats due to never having flushed the coolant.