New Apartment Construction

[William Frankel]

i was wondering what people thought of the best unit mix for new apartment construction?  on the one hand, the smaller the units (studio and 1 bed) the higher the price per square foot for rent.  on the other, the larger units (2 bed+) have longer tenancy but lower per sf rents.  when turnover and vacancy costs are factored in, which units maximize profits?

i am looking at building a 30 unit apartment.