Tax related question regarding percentage occupied

[David Cha]

Hi BP

just purchased my first house hack, mande tons of mistakes, but learned so much from the podcasts. I am trying organize my finances and will be speaking with a CPA but and am trying to maximize all my deductions, but I wanted to have an idea of what to expect. 

The layout is a triplex where all the units are the same size, however unit 1 has exclusive access to an unfinished basement, porch and backyard. Does this unit take a bigger portion of the percentage that is deductible, or should I still assume it is a 1/3 split, percentage wise.