There are shims available to correct pulley spacing if necessary. I believe I've seen them listed on Ebay. You're right about getting "close enough" though! Depending on the distance between pulleys, I've run belts with 1/8" or slightly more misalignment without any problems.
Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!