If someone is going to talk on your behalf, its going to be however they want it to be, whenever they want it to be, to whoever they feel comfortable with in the department, in whatever method (phone vs email) they want. Trust faculty to make the correct decision for you as an applicant and be grateful no matter what.
Several surveys/studies of residency selection have shown that applicants dramatically over-value 'the phone call', whereas program directors say they aren't really very important in the grand scheme of things. It is worth a shot, but don't think it will have a huge effect.
