After dealing with it for over a year.... All it took was loosening one bolt on my alternator, tightening one bolt that positions the alternator, then re-tightening the first bolt. Took 2 minutes, tops. Everything easily reachable from above.

I am now seeing 14.5 volts immediately at startup, instead of 12 with a three minute wait to get voltage up to a good level. No more squeals! I can’t believe I lived with this so long. I was scared this would be a big job and I’d fuck it up and make things worse. But no... Two bolts. That’s it. I’m both happy, and shaking my head at myself! The belts actually looked to be in good shape. I ordered OEM replacements for both accessory belts, but for now I’m just going to call it good and keep the spare belts in the car.

Oh, added a Blackbird fabworx tow strap as well. Any recommendations for a tow strap that would suit my little Miata?