Transient Calcs for Residential Occupancy within Mixed-Use Dev.

I was wondering if anyone could provide guidance for calculating the transients for the residential component of a mixed use facility? We are working on a multi-story mixed-use development that includes office, retail, and multi-family residential. The FTE and transient calculations for the office and retail components are pretty straight forward, but I have been unsuccessful in finding any references to calculating transients for residential occupancy. Table 1 in Appendix 1 of the Reference Guide provides default occupant per square foot numbers for multiple occupancy types, but nothing for multi-family residential. I may have missed it, but I could find no such reference in LEED Homes either. I would think that we would need to account for some degree of transients/visitors for the residential component as the apartment tenants would likely have visitors who would possibly use their restrooms; and there would be prospective tenants meeting with leasing staff, who might utilize the public restrooms. Certainly this isn't the first mixed-use and/or multi-family project to pursue LEED certification. What have others done for this occupancy type? Is there any guidance or rule of thumb published anywhere that I may refer to? Thanks in advance for any help!