Nick,
When kermeo plans to write a short essai for a lecture about recording and mixing classical vocals, my last sentence is perfect to start with. But it will be difficult to make a close to reality text for a person without any experience.
If he actually want to do a recording of a classical vocalist, there are no fixed rules how to do it. Then he should initially mention what the music is, i.e. Vivaldi, Delibes, Monteverdi. By what is the vox accompanied, what is the composite of the ensemble, i.e. chamber orchestra, a duo with piano, an orchestra. Is it a male vox, female vox, or mixed choir. Is the recording done in a concert stage, what are the dimensions of the room, recording in a church, in a recording studio. Then it starts to make sense going into details.