Allocating expenses for house hack

[Josh Dillingham]

I have a three unit building in which I occupy a three bedroom unit and rent out a 2 bedroom unit and a 1 bedroom unit. I am planning on allocating the expenses as 50% rental vs. 50% personal based on square footage. Is this what is required or could I allocate 33.3% as personal and 66.6% as rental because 2 of the three units are rented, even though my unit is bigger than the other two?