We sing Vespers weekly.

For the reciting tone, we sing on A (La). In France and in the Francophone communities, a lot of people sing on B-flat (Si-flat). Whatever you do, make that pitch the dominant/tenor of each psalm and antiphon, the Deus in adjutorium, the versicle. The hymn should be what is comfortable. I suppose that you may know that from the monastic office, but I have seen books where they change the pitch of the dominant from one psalm to the next, and it drives me mad. There are a couple of options for booklets. These are indispensable particularly with a translation.

The seculars sit at « Sede » in ps 109 and don’t don’t rise for Gloria Patri. The person intoning rises for each antiphon (and sits if not the cantor), then the cantor rises (if a different person) and intones the psalm. Sit at the asterisk if you don’t do the full ceremonies. Stand together at the end of the antiphon.

The celebrant in my experience intones the hymn even if you don’t do the full ceremonies with acolytes and incense. The Audi Benigne only has one melody, so that’s easy. The versicle tone is the one used as on all days except solemn feasts.

In the former PCED communities the custom to sit as on doubles after the celebrant intones the Magnificat antiphon was largely retained. You sit for the repetition and when that is over, you stand until the end of the office on Sunday.

Otherwise as to music, particularly in the Francophone world, following the classical Solesmes musical practice as in the Liber is pretty (more) common. I know of more places not doing that for propers versus Vespers, honestly.

Yeah but I wasn’t sure what language would be required on the other side.