We have sung Gregorian propers and Gregorian hymns as verses to popular refrains. For example "O Holy Mary" with Ave Verum, Taize " Eat this Bread", with Qui Manducat, This lets you fly under the liturgical radar and lets you say yes to some of those tiring suggestions from the committees. It satisfies the active participation prerogatives; it maintains a unity and edifies the congregation that needs to develop an ear for the full Gregorian propers.
It is so important to have everyone ready for the propers. I am typically a little shy with introits, using them only for incensing music. But on Christmas morning, just minutes before Mass I simply suggested to the pastor that we forgo the elaborate processional hymn and just sing the introit acapella. His response was "That would be wonderful." He asked me to say a few words to the congregation about participation through listening and the role of the propers. I was ready, the men of the schola were ready and the congregation was ready. I explained to the congregation that I was not at the ambo to teach Them some new response but that they would be hearing an important introit today - An actual Christmas morning dialogue between God the Father and Jesus! We were all excited, alert and relieved!

Christmas was Great at St. John's!