James, I enjoyed reading of your experiences and views. I played clarinet in school bands and orchestras many years ago, but my present active musical life involves singing in the choir(four women, two men)of the Eastern Rite church I belong to. The singing is more nearly that also heard in Orthodox churches, rather than in the Latin Rite of the Catholic Church, and no, nothing quite on the scale of the Missa Solemnis.
My own listening is almost entirely classical(about 1000 discs)and my favorite Missa Solemnis performance is the Solti in Berlin(not the Chicago), available
here as used copies for very reasonable amounts.
For TOOL and others who might be interested in getting into Beethoven, the symphonies would probably be a better starting point, and I'd especially suggest the
Kleiber performances of the 5th and 7th, and the
Wand performance of the great 9th, all of these being available at scandalously low prices.