For future reference the paint we used on the boat is:
Behr Premium Plus Exterior Semi-Gloss Enamel. The air boxes are this Ultra Pure White and took half a quart for a single coat on the boxes and a coat on the oars.
I bought a gallon of the green called Chlorophyll with the chart below. A single coat on all the parts so far has used about a third of a gallon, but we haven’t painted the bottom yet either. Two coats everywhere will probably get us close to using the whole gallon.