Working out which side of the ship gets more sun depends on your itinerary and the direction you are sailing in.
The sun rises in the east and sets in the west, therefore if you are sailing south you will get more morning sunshine (weather permitting) on the port side of the ship.
It is likely that both sides of the ship will have an equal amount of sunshine however this will be, for example, port side on the way out and starboard side on the way home ... or vice versa.