This general guide to using an air paint spray gun can apply to conventional air paint spray guns, HVLP air paint spray guns and LVLP air paint spray guns in gravity feed, suction or pressure feed variants.
The first thing to check is the paint manufacturers technical data sheet which will recommend a fluid nozzle size and often an air paint spray gun type for use with their coating.
The technical data sheet should also specify maximum thinning that is allowed for air paint spray applications.