This has worked quite well for me in the early game. The reason I say this is that propulsion tech can and will outstrip your ability to maintain effective tracking speeds. For the long game you still need light/fast anti-missiles to counter salvos.
Can't you just keep cranking up the turret speed at the cost of additional mass?
At some point the turret mass will no longer be cost effective. Consider the following.
Quad 12cm C4 Far X-Ray Laser Turret
Damage Output 4x4 Rate of Fire: 5 seconds Range Modifier: 8
Max Range 320,000 km Turret Size: 22 Armour: 0 Turret HTK: 8
Power Requirement: 16 Power Recharge per 5 Secs: 16
Cost: 286 Crew: 160
Maximum Tracking Speed: 32000km/s
Quad Gauss Cannon R5-100 Turret
Damage Output 1x20 Rate of Fire: 5 seconds Range Modifier: 5
Max Range 50,000 km Turret Size: 32 Armour: 0 Turret HTK: 8
Cost: 280 Crew: 96
Maximum Tracking Speed: 32000km/s
Laser is 22 hull, Gauss Cannon is 32 hull. Both have a rotational speed of 32,000 km/s (based on the max fire control).
For 32 hull, I can mount 16 of these.
Maximum Missile Size: 2 Rate of Fire: 10 seconds
Launcher Size: 2 Launcher HTK: 1
Cost Per Launcher: 22 Crew Per Launcher: 20
16 shots to 4. Okay, comparing RoF, 16 shots to 8. The laser needs a power plant, so assume another 5 hull for that. 27 hull for the laser/power situation. Still 13 AM-Missile launchers for the size. Of course, you need magazines.
How about this
Maximum Missile Size: 1 Rate of Fire: 5 seconds
Launcher Size: 1 Launcher HTK: 0
Cost Per Launcher: 16.5 Crew Per Launcher: 10
Put in these missiles.
Missile Size: 2 MSP (0.1 HS) Warhead: 1 Armour: 0 Manoeuvre Rating: 82
Speed: 32000 km/s Endurance: 94 minutes Range: 180.0m km
Cost Per Missile: 3.1167
Chance to Hit: 1k km/s 2624% 3k km/s 820% 5k km/s 524.8% 10k km/s 262.4%
You'll notice the range is over 500 times the max range of the laser, and 3600 times the range of the GC. Of course, this is also assuming you have the electronics to back this up. Firing at the following missiles
Missile Size: 8 MSP (0.4 HS) Warhead: 48 Armour: 0 Manoeuvre Rating: 10
Speed: 32000 km/s Endurance: 94 minutes Range: 180.0m km
Cost Per Missile: 16.2667
Chance to Hit: 1k km/s 320% 3k km/s 100% 5k km/s 64% 10k km/s 32%
You are still talking about an 82% chance to hit.
Same RoF as the turrets. And you can cram in 20-30 times the number in the same space. Assuming you are going to replace the GC turret with missiles. Go 20 AM-launchers, and 4 magazines. 200 AM missiles for defense in that scenario.
Of course, neither the laser or the GC will run out of ammo.