re: "...The old one has been sitting in the garage at about 50 degrees for two weeks and it still has a charge of 12.4 volts. The new one that gets driven everyday only has a charge of 12.06. I'll post the results of my tests...."

Well, clearly, that's not as it should be. Wouldn't you expect the new battery to have a higher charge than the old one?

When you installed the new one, did you scrupulously clean the terminals?

By the way, and this is just an aside, do you have the version of a '93 with just an ordinary positive cable? Or do you have the '93 version that has the positive cable's battery clamp being combined with an array of four fuses?
I have two '93s, and one just has the ordinary cable, and the other has the unusual cable (four fuses in a mount that's integral with the positive cable's battery clamp). If you don't understand what I'm talking about, then you have the "ordinary" cable, because the other one is quite different and unusual.
I've been wondering about this, and from my two cars' VINs, I speculate that the change was incorporated in the middle of the model year (my car with the unusual cable has the higher VIN of the two, ...4276 vs ...0769). I was wondering what version you have, and whether your VIN is closer to my higher or lower number, just to see if its a matter of when the car was built. Thanks.