[MetroMPG]

The forum's tire expert (CapriRacer - tire engineer) will tell you that rolling resistance outweighs other minor variations (eg. weight, circumference, width).

So unless you know the tires have exactly the same rolling resistance (in which case I'd say the narrower ones would win out through lower aerodynamic losses) the only way to tell would be to test the 2 sets of tires against one another.