Argentarius,

Unfortunately, the situation isn't as simple as you propose. Historically speaking, there are some church buildings with a special feature called a "quire", where the trained singers and/or monastics sit for antiphonal singing. In modern times, when there is no architectural feature noting the sanctuary, and none marking the Communion rail, choirs are often placed behind the altar, facing the people, or prominently obscuring the altar. These are bad ideas.

Can a schola be placed on the first step of the sanctuary? I've seen a schola at the transcept in a parish which is unarguably traditional in its praxis.

Yeah, I know, but debating the appropriateness of hymns at Mass isn't going to solve my problem. The parish is four hymn standard. The organ sits in the front of the first pew, so putting the choir in the loft is not workable. They currently are in the front pews with one mic. The church was built in the 60's and obviously no thought was given to any of this. To move the organ is an expense the parish cannot handle. I do not like the idea of choir members standing in the sanctuary. It seems so irreverent and likely lead to confusion, them going back and forth, - and which book do we need now ? and I forgot my glasses etc. - I'm being pushed into this by a vocal parishioner and a pastor who should but doesn't know better.

This presents the unique challenge of determining precisely where the musicians are best accommodated ... as both worshippers and ministers. A location which positions the musicians within the assembly at a non-intrusive but somewhat forward space, and which, at the same time, allows their view of and attention to the altar/sanctuary is to be desired. http://www.odwphiladelphia.org/wp-content/uploads/2014/02/LocationofChoirandMusicalInstruments.pdf

De musica sacra et sacra liturgia III-4 (1958): 67. The organ should be located in a suitable place near the main altar, unless ancient custom or special reason approved by the local Ordinary demand otherwise; but the location should be such that the singers or musicians occupying a raised platform are not conspicuous to the congregation in the main body of the church

Some choirs could be placed in the parking lot with no harm done to either liturgy or parishioners.

It's too bad. The choir shouldn't be a distraction, so seating them and then having them stand would be the best alternative... but as to having them move, well, that is a real distraction, and gets the ego bird in motion not to mention the large distraction away from the liturgy itself.

Perhaps a picture and a clearer description of the room and it's acoustics would help

Two scenarios that require working with odd architecture:

1) local parish, really unchurchlike modern building. "sanctuary" is a raised stage-like area that goes fully from left to right, wall to wall. Altar takes up a small part in the middle, there is one podium from which all readings and the psalm singing are done. The areas to the sides of the altar are not needed for active liturgical use. One side has some chairs and large statuary. The other side is used by musicians and choirs. They have the electronic organ on the main floor, by the wall, and then the singers arrange two rows of chairs facing the congregation. They stand to sing and sit when the congregation sits. They move to the first two rows of pews nearby for the Consecration, then return to their chairs. They are visually some 40 degrees to the right of the altar (for a congregant sitting in the middle of the church), so they aren't distracting. They wear modest white shirts/blouses and black pants/skirts. Additional instruments like guitars, saxophone, drum, etc are on the floor level along the wall near the organ. During the week, when there are just one or two singers, they stand next to the organ on the floor level, facing the congregation, but off to the side enough that one doesn't notice them much.

scenario two: centuries old church which used to have a sanctuary, an altar rail, then an area for the seating of the confraternity, then another altar rail, then the area for the public congregation. After the Post-Conciliar altar adjustments, the first altar rail was removed (the holes are visible in the floor) and a wooden platform was built to extend the sanctuary into the former confraternity area. The other altar rail was left in place. So what happens is the former confraternity area, which is quite large (could seat 50) is now "the sanctuary". However, we are overflowing every Sunday, with people sometimes fainting in the tropical heat, so the priest asked us to just use some extra rows of chairs along the walls in that area, leaving the front row on each side for the servers and such. In order to facilitate Communion the choir also runs down from the choir loft right after the Agnus Dei, mumbling the Confiteor along the way, kneels behind the altar servers who are going to receive Communion first, then moving over to the side of that area to sing the Communion antiphon and psalm while the rest of the congregation receives and the priest goes back to the altar. When he shuts the tabernacle door we wrap up the psalm and head back upstairs, which gives us a moment to catch our breaths and then sing a post-Communion hymn.

It's weird working with the great variety of architecture, liturgical styles, instruments, and other variables...

Just about the best arrangement, is seen in my local Anglican church. This view, which is not liturgy, has the ladies of the choral society in the stalls designed for the choir.

Elderly people haven't always been as prone to need elevators, cushions, kneelers, hearing aids and such....

CatherineS , the singers face the altar, they have microphones stands which they use. When I sang in the choir (1977 - 2010); there were several who who walked up the choir steps despite the difficulties it placed on them. I remember John Petros who was 90 would come up. I think when walking up steps becomes painful it's up to that choir member to see the wisdom of not continuing.