that contact the pully and that causes some of the squeeeeel.
Best not to overtighten the belts beyond factory spec for used belts. Note that tightening the 3 belts Alt, PS and AC can be a PITA if not familiar with the connections. The PS especially can be a devil because the main PS pivot bolt is only accessible thru a hole in the pully face when lined up properly for a rachet and socket. AC easiest from underneath. The alt also needs to be done from underneath.