Three ships or two pairs for mutual support?

Would four ships be better than pairs or a three-ship group?

Three provide a mutually supporting pair and one ship in overwatch; the argument for four is that the overwatch ship would then have a partner too.

A three-ship arrangement sends two vessels forward together while the third observes the wider situation. The pair can support each other without committing every ship to the same immediate encounter. A four-ship group could instead divide into two pairs. The extra protection remains a competing preference, with no agreed group size.