My question - what are the most effective y wing builds people field? Trying to give them another shot, despite their obvious weakness.
Their weaknesses are a poor main gun and a bad dial. You can get around both issues very easily by slapping on a secondary weapon and making it a turret that doesn't require fancy manoeuvres to get targets in its arc - hence they were practically made for Ion Cannon Turrets.
The most common way to run them (and the way I always do) is Gold Squadron + Ion Cannon = 23
If you want to take them a bit further, the next thing is to realise they are still fairly useless at Range 3. The Ion is only range 1-2 and at range 3 the enemy get extra evade dice vs the y-wing's paltry 2 shots, so what I do when points allow is add a Proton Torpedo.
"4 Attack Dice at Range 2-3
Attack (target lock): Spend your target lock and discard this card to perform this attack.
You may change 1 of your Focus results to a Crit result."
It's one shot and costs 4pts, but it does increase your squadron's damage output in the vital first engagement. Also note if you fire them after any other weapons have stripped shields or evade tokens you have a decent chance of getting a crit through.