MaryAnn,

Since you work in an EF parish, of course your big questions are whether to sing one Gregorian ordinary or another. When I plan EF Masses, my concerns are similar to yours (though at a much lower level of execution on the polyphony--your choir is outstanding!) In most OF parishes, despite the best efforts of Rice, Tucker, etc., there are 3-5 hymns sung per Mass per weekend. In my setting, I make a minimum of 12 hymn decisions, in three languages, per weekend. Triple all of that for a multiplex parish gig like Charles'. Talking about hymns is not a "distraction," it's a help. Why are these helpful threads constantly being diverted?

About the original question: in the early 90s I took a series of liturgy classes. One of the teachers showed a chart in which the emotional content of the different aspects of the Mass was shown by the length of a bar in a graph. Moments in the Mass with a low level of dynamism had a short bar, moments with a high level of dynamism had a long bar. The Alleluia and the Amen had the longest bars. In some big Cathedral Masses, I have heard this sort of graphic design played out with volume levels. For those long bar moments, here comes the timpani!

I don't think this is an authentic High Church tradition, but more of a High-Church-Does-Broadway style. The music documents over the centuries have constantly tugged liturgical music away from showmanship. The Broadway musical is our era's opera, as it were.