I just composed this set of alternatim choir invocations for use with Mass XI.

Designed so that the choir verses are of the same length as the chant verses, and using the cantus firmus in such a way that it is easy for the congregation to pick up their cues and sing.

We'll be doing it here on Sunday, with the assembly verses accompanied -- but maybe someone else will find it useful? Also included is a recording of the setting (just played on keyboard by me) to give an idea of the flow.