alternator pulleys

I just noticed this when swapping out my alternator... there are two different sizes for the alternator pulley. one is a smallish thing about 1-1.5" in diameter... the other is about 2" in diameter... which one is better?

I know the smaller one would give more amps at lower RMPs, since the thing would be spinning faster, but the larger pulley would put less strain on the rest of the system, since it would be like a higher gear ratio, like the underdrive pulley thing.

Iirc the alternator is only putting a load on the motor when it is generating current, The regulator will not let it put out more power than needed. It would seem that either pulley will not increase total load on system. Things to consider are if you are putting a higher than normal load on your system such as stereo's or electric fans you may want a alt that starts cranking out amps at a lower speed to keep up. Also whether or not alternators have a max rpm that they should not exceed. Points to ponder. Dan242tic