I know you liturgical musicians were wondering if we were going to get to psalmists, cantors, and all. Here we go. One section:
56. The psalmist, or cantor of the psalm, is responsible for singing, responsorially or directly, the chants between the readings – the psalm or other biblical canticle, the gradual and Alleluia, or other chant. The psalmist may, as occasion requires, intone the Alleluia and verse. 
For carrying out the function of psalmist it is advantageous to have in each ecclesial community laypeople with the ability to sing and read with correct diction. The points made about the formation of readers apply to cantors as well.
I prefer using the term “psalmist,” as the term “cantor” implies a wider role and doesn’t really apply when there is a schola, ensemble of singers, or a choir.
Not a surprise that the three-fold formation of lectors will apply to psalmists as well. I know of many lector resources that get fairly deep into biblical formation, but much fewer that attend to the full pedigree of the Psalter. Do your psalmists know the background, genre, style, and meaning of the full psalms they sing?