stryped fired this volley in
:

I am looking for an easy and accurate way to check pulley alignment
on the serpentine belt system

You're not really thinking this out, Stryped.
Everything in a serpentine system is rigidly mounted. There are no
adjustments for lateral alignment. Belt tension is provided by a spring-
loaded tensioner.

The tensioner bearing is the most common problem, and they're cheap to
replace, but a mother-bitch to get to in some of the compacts.

The Mazda AC compressors have the same basic defect as the Mitusbishi
ones. The front of the pulley is vented, and the vents are so large that
there are only three little 5mm tabs of steel holding the entire pulley
to its spline hub. With time, they flex JUST enough to crack.
Eventually, if that happens, the pulley will let go of the hub. It won't
fly off, but it will create a terrific racket and possibly break your
belt.

If one or more tabs are cracked, you can see that as a wobble in the
pulley, whether the AC is on or not.

And you never said whether or not the AC is working properly. You could
have a plugged system deadheading compressor pressure, and causing the
belt slippage.

Still the idler is most suspect, then probably the AC clutch/pulley,
followed by the alternator bearings.

LLoyd