I never spray paint the railings as it uses too much paint. I find the hand painted enamel works a treat, especially the runny stuff I've got in this batch, as it runs around the curves.
I managed to construct some of them outside of the boat so painting was easy. However, some were constructed 'in situ' as the compound curves were awkward. These were painted on the boat very carefully. Even so, the next day I looked and found some runs from the stanchions onto the deck. It wasn't much but this now looks like tiny white washers around the base.
ken