I use 3/8" round rod, a very straight rod. I gently bend the rod around something round in the same diameter as the pulley groove. Make sure you start out with a rod that is long enough to reach the pulley you want to line up with. You put the radius bend of the rod into one of the pulley grooves and use the straight end to lay into the pulley groove of the other pulley. The bent part of the rod in the groove of one pulley will give up a very straight line to line up any other pulley. Adjust the P/S bracket until the straight part of the rod lays all the way down into the groove and it should be pretty lined up. It helps if you have someone help by pressing the curved part of the rod into the pulley groove as you manipulate the straight end of the rod. I've even used a clamp to clamp the curved end into the pulley to make sure it stays pushed all the way into the groove (this is important).
Once you put a nice curved bend in the rod and lay it into the pulley groove you'll immediately see which way you need to adjust the P/S bracket. A blind man could "feel" when they are properly aligned because there's only on spot where the rod will fully engage the pulley on the curved/bent end and also lay perfectly into the groove of the second pulley!! If the P/S pulley is cocked even as little the straight portion of the rod WILL NOT sit all the way into the pulley groove.
GOOD LUCK>>>.
treblig