Okay, two points:
(1) Everybody who disagrees with WonderWAAAGH is right: based on the information FFG has made public, the YV-666 appears to have an auxiliary firing arc (two of them, actually). It is entirely plausible that these operate just like the Firespray's auxiliary firing arc.
(2) WonderWAAAGH is also right: exactly what the "auxiliary arcs" are or do are in the realm of speculation for everyone except FFG's design team and playtesters. FFG could, if they wanted, print that exact ship chit and define those two shaded spaces as Super Duper Arcs where the YV gets an extra attack die. FFG could define them as Nasty Blind Spots, and rule that the YV can't shoot at anything within the auxiliary arc.
So asking whether triple-YV builds are going to be a thing, let alone planning to stack multiple Tacticians and abuse (what people assume to be) auxiliary arcs, is putting the cart in the next county over from the horse.
