Hey guys just putting my two cents in for the forums.
Turns out that the combo does work for phatoms quite well. Often you roll 1 or 2 hits (average) with a focus thrown in there. This makes it possible for almost all ships to evade expecially at range 3 or ships with a stealth device and/or a token.
In all the games I used this combo gunner has either destroyed the ship or allowed me to put damage on set ship.
I recommend only 3 ships have the upgrade however.
Sigma Squadron Pilot, as they shoot @ ps3 and need to put on damage as much as possible
Or
Whisper- Load whisper up with Advanced cloaking device, Vi, Gunner, FCS. It is a big point investment but you do get your weight in damage and a free focus/cloak after you attack. Once you have your TL you won't use gunner much until the targeted ship is dead but even still, you are able to reroll all of your first shot then gain the TL and gunner again, maximizing your damage potential.
Echo can be suited well if you run it right, use his ability and put an engine upgrade on him, making him almost impossible to figure out his final position. Give him VI (just to help), and gunner/fcs. This allows him to roll all over the board and use his action with boost. Shoot miss get your lock/second attack and you are good to go.
I don't recommend the middle tier guys simply because they are shooting in the middle of the pack at PS5. Give them SPA so they get that evade to use early or later in the shooting phase.