Leismo de cortesia and consistency?
I've read about the "leísmo de cortesía" i.e. the use of "le" and "les" as direct object pronouns when referring to a person or group you are addressing formally. Most of my learning resources never advocate using "le" or "les" as direct object pronouns. However, some (e.g. Michel Thomas) seem to teach "leísmo de cortesía", at least in the singular (I'm not clear on whether the Michel Thomas courses employ "leísmo de cortesía" in the plural). My question is: take a speaker of peninsular Spanish who says "puedo verlo" for "I can see him" but "puedo verle" for "I can see you (sir)". Would consistency require that such a speaker use "puedo verles" in preference to "puedo verlos" for "I can see you (plural, formal)"? Or are there speakers who employ "leísmo de cortesía" in the singular but not the plural? Is this viewed as acceptable, or would this seem inconsistent to a native speaker?