What I'd really love was that if you did the Lancer justice and made it a fighter killer to end them all with 20 anti-fighter lasers. If the ship has six slots (how many slots do they have max in FS? Six? Ten?), then that's 20 divided by 5 players, which is 4 lasers each. If you give each player the option to choose where the fire intersects, you should be all set for some fighter-smashing.

Massed AA guns worked (and works) like this: Basically, instead of trying to hit the target directly, you "draw" an imaginary cube that you then fill with anti-aircraft fire. This "box" is often "drawn up" in advance, based on what is believed to be the target's path to or from its target.

So basically, when the enemy flies into the "box", the guns let loose until the target is destroyed or has left the "box".

Actually, you can have more turrets than the limit allows, but the weapon you want on the ship must act as a seperate turret, with the entry point somewhere within the ship. Though I suppose you could make a battery of guns and code it as a seperate turret. This would be useful for capital ships if, say, you want the Imperial Victory Cruiser to have  laser cannon batteries in the trenches for point defense without sacrificing anti-capital firepower.