Rows 1-16 in section 506 have 24 seats per row. In row 17 there are 27 seats. As you face the field from this section, seat 1 is on your left.
You won't find the best views from the upper portion of Citi Field's highest seating deck, but what you can find is a nice cheap ticket for taking in a Mets game. Staying between the corner bases from this height helps to keep you more dialed in to the action due to the proximity to the infield, and line of sight to the center field videoboard.
Most sections feature 17 rows of seating with entry tunnels below the very front row. Coverage is limited, but can be found in the last few rows if you don't mind having the highest seats possible in exchange for some protection from the weather.
There aren't many seating areas at Citi Field which don't have access to a Club area, but these are some of those few which do not.