Ace can mix colours for oil and latex. Sin Tung Hing Marine carries several marine paints.
Linear Polyurethane is available at Polynesie Penturestel 40 53 17 53 in Fare Ute on Voie M. One of the staff speaks very good English. They can mix any colour. Assuming you are "roll and tip'ing" or foam brushing then avoid the fast hardener, best to use slow or normal also Be sure to get normal thinner not fast. They also have the very best price on zinc based primer by far. For foam brushes go to Ace but small mixing pots go to Sin Tung Hing Marine. Sin Tung Hing and Ace both carry respirators with organic filters. In the heat here any masking tape except 3m will leave a horrible messy glue residue Sin Tung Hing carry an assortment as does Nautisport and Ocean 2000.