String quartet, or octet? How small a stage are you talking about, Fran?!
Anything that can't fit an octet, that's not a stage... that's a postage stamp! You place the singer/guitarist in the middle of a semi-circle of string players, that's still pretty intimate.
Thing is, Col used a TINY room around the voice. It it were matched to the size around the guitar, there'd be room for the string section. And all this is simply a guideline. Adjust your room for the size of the ensemble you intend to put in it. Plus, the size of the room and the size of the STAGE are two different things. You can have small stages in quite large rooms, and vice versa. The POINT was consistency, rather than size...
All good points Diki, in theory, but in practice - one rarely hears a band of larger than 2 pieces without vocal processing. That practically eliminates the natural sound of the room/space. As a singer first and musician second, I make my voice sound the way I want before I even consider any other sonic enhancements. Your advice was good from an engineers point of view, but as a live performance - I think Col made the right decisions.