Miacoyne,
When we offered our Christmastide Concert I invited our local "garage" schola to participate for the first time. They, too, had some hesitation simply over the notion of concertizing in the sanctuary. It occured to me immediately to propose that their participation in the event could (and did) serve within the framework of a "sung prayer service." Their director concurred, developed their own order, and it was all beautiful. Of course, their singing three seasonal Introits does not a concert make. So, if you're the centerpiece of a whole concert event, issues such as singing Ordinary movements, Proper chants or chanted hymns would require some deft planning.
I remember hearing Shaefer's Gonzaga Schola at a national ACDA convention's "Sacred Concert" in LA at the then new cathedral. Their portion was the only one wherein a sense of "sacred music" touched my soul. But, again, it was not the centerpiece, but part of a pastische.

As with the parishioners at Mass, I think it would be a great help to the people attending to be able to see the words and translations in print. When they see how lovely the text is, it will help them understand the beauty of it... if you have some historical tidbits to add to engage them (like the history of a particular piece, who wrote it... how old it is... when it was typically sung, etc.) that would even add more to it, I think. I had a bit of extra room on one of my Holy Week programs, so I put a shortened version of the Te Deum (with English translation) and also a short excerpt from Catholic Culture about it as well.

Think about changing your focus from a 'concert' to a prayful event. It's easy. For example, Gregorian Chant through the 4 liturgical seasons. You could choose
the 4 Marian Hymns as the framework & supplement with chants of each season. Have someone simply read the text of each chant as a prayer before you
sing. Or a reading from scripture. This is a wonderful way of keeping a spiritual focus.

Just an idea. Good luck.

It would be quite nice to present chant and polyphonic settings of the same texts.

Our schola will have our 'Performance' next week. Last night, we had a brief, healthy discussion on whether we should address to audience to hold the 'applause' till the end, or don't even have applause at all. This really helped us to think about our singing chants in general.
One of my schola member sent me a beautiful email in this regard. I wanted to share his thoughts here. He hasn't sung chants for a long time, but he really understands and appreciates the beauty of the chants. I'm so proud to say that I'm learning from my schola members now.

"I have thought alot about the situation of the concert.

For me it is a performance in the sense that the fellow faithful will receive it as something new and revitalizing. If we are dusting something off, we are presenting it anew. In this sense it is a performance, a presentation: submitted for helping reawakening. Just as the Church has applauded the Solesmes monastery and its experts for reviving chant and codifying the treasury of it, so should anyone be recognized for the mission of re-evangelization through the chant. "The laborer is due her reward" in this regard.

This role however is always historically temporary. So if applause is merited it is necessarily short-lived and even limited, because the "dusting off" soon becomes complete and now we enter into the actual life of the chant itself, which is pure prayer.

On the other hand, chant achieves something perfect which is the mystical union of prayer and musical sound; God and soul, they become indistinguishable from one another. It is a bit like the St Francis quote: "Humility is a quality that if a man knows it not, he possesses it not. If he possesses it, he knows it not." You cannot really be an observer outside it to even suggest the idea of performance. What [N] said last night therefore struck me too as true. (on his comment 'why do we get an applause for praying?) But the chant in our time is wrapped in multiple contexts.

In the end, the key is audience preparation with artfully chosen description of what is taking place, acknowledging the above and yet still other aspects. The Chant challenges and transcends the very ideas of concert, audience, performance: because it always seeks union: all his people and God with his people. The chant is ideally unitive, there is no schola and audience, there is only God.

Pope Benedict touches on these things toward the end of Spirit of the Liturgy; he acknowledges that certain uncomeliness can occur where the focus is no longer God, but human egos. But he also openly recognizes the hardwork of persons who make such gifts of beauty possible to the church. It has to be a balance of some kind: we are happily lost in the body of Christ and yet we are unique persons too. Maybe this is what the response (the development) of polyphony means to the chant? The reality of parts and whole; unity and diversity, all as God intends.

it all goes on... : )

may the Holy Spirit guide us all Amen."

What a wonderful thing... I look forward to hearing more this summer at the Colloquium... J.

Mia, congratulations! I love "Christus Vincit"--would have loved to hear it.

Mary