I run Garven / rookie Xwing / gold Ywing + ionC / Dutch + ionC +R5K6. I usually fly them in a square with the mooks in front, and the Xwings and Ywings diagonally across (I tend to put Dutch on the right, because I'm right handed). The Y wings will always be together, while the X wings will be buzzing around. Do also note that eg. the rookie Xwing, after doing a koiogran turn, can get garven's focus token and Dutch's target lock, because those aren't actions.
damage from ion cannons is capped at one, but when you have a total of 6 actions per turn (7 if you are lucky, of which both Xwings will have target lcoks AND focus), I am able to drop a regular TIE on focus/evade at range 2 or nearer (range 2 because ion cannons only shoot that far out) with near 100% confidence, and heavily injure TIEadvs, getting them down to 1 hp most of the time or outright killing them in 1 turn. I've not tested this against a rebel squad yet, but if it can down TIEs that quickly, I doubt it would fare too badly against the rebel ships which have lesser agility. Losing either Garven or Dutch would'nt hurt the squad too badly either, as you still have the other around to give the bonuses, and all of them are at similar ps, so you can specifically choose who to fly first or attack first to get the correct bonuses going here and there and so on.
The Ywing may only be able to deal 1 damage with their ion cannons, but normally with 3 attack dice against 3 defense dice and possibly an evade token as well, you would still be doing about 1 damage either way, that's how i see it. With target lock, that's like a confirmed 1 point of damage + ionize. regular TIE fighters have 3 hp, so 1 damage is actually very painful for them. of course, if you manage to get any of them in range 1 of your regular pewpews, just blast them away with your regular pewpews. Oh, and due to their higher hp, slower speeds and perceived uselessness, I tend to run Ywings in front of Xwings actually.