I would imagine you'd be visually and aurally happiest somewhere two-thirds to the back of the orchestra, somewhere a little left of center, or first balcony, also left of center, or perhaps even closer to behind the pianist. Usually you wouldn't want to sit in the exact middle, or you won't see much of the pianist's hands, but neither do you want to sit directly behind the pianist on the balconies, as their head and shoulders will block the keyboard and you won't see their expression.
I recommended two-thirds of the way back because of the slant of most concert halls I've been in… depending on the height of the stage, this might not be optimal. However, I think anywhere behind the halfway point in orchestra, or balconies as long as your somewhere left of center, will make you happy. His Concerto No. 2 is fantastic, and you'll enjoy it regardless.