If belt is squeaking, tighten it up a little. Subjective to say how tight is just right, belts are flexible and geometry can be whatever. But comfortable saying this: If it squeaks, it is too loose. Or something else is making the noise.
Yep, check batt volts with engine (and charger!) off. Normal charged batt is 12.6 or so, can be a little higher if you just turned the charger off.
Then start engine and rev to say 1000rpm. Check volts again. Should be 13.8-14.2, but the Balmar regulator may go a bit higher than 14.2 until it senses batts are topped off. See those volts and alt is fine.