I did a number of little watercolors while I was on Vieques last week. Most are done on a 6"x 6" block of Fluid watercolor paper. The horizontals are half sheets, about 6" x 3".
These were done at Playa Media Luna (Half Moon Beach), a lovely protected cove (although there should be more space between the two paintings than there is.) My advice, if you're going to paint on a tropical island- bring turquoise!