Very poorly. I had a friend with a 173, URM, and 3.7 GPA who checked two boxes instead of one (Native American and Black). The best place he was accepted into was a T3. He curses the decision to check both boxes even today.
No, seriously, that didn't happen. You'll be fine checking two boxes. I can't see them possibly caring at all and they might even credit you for "thinking outside of the box" by checking 2 boxes... so to speak.