Well, cruise-stage cluster missiles are seem like a no-brainer meta from my perspective, somewhat contrary to previous posters. It allows you to create a missile that is capable of efficienty bypassing heavy PD/AMM protection at a relatively low cost. It is indeed having rather low reaction time comparing to fighters and long time from launch to hit, but is more warhead/shipweight efficient than fighters (which need hangars, carriers, magazines etc. ) and is more sneaky on approach (most fighters can be detected outside of their launch ranges if they use fast missiles, also fighter has to carry sensor and MFC which is hard to have big enough for out-of range hits).
The general approach in design is that you want high range, higher than your sensor range as the missile flight time may be extedned by enemy moving out. For example if enemy is 5k/s and cruise stage of your missile is 20k/s then for your sensor range you would want additional of about 5/20 or 0. 25 = 25% plus a padding for missle range 125%-150% of active radar range. For faster targets you would need to manage your launch distance to ensure missile wont run out of fuel.
The design examples are (made on on Magnetic Confinment Fusion, 0. 4 fuel efficiency, 8 wh strenght, 100 agility):
Cruise stage:
Burya-IIIM
Missile Size: 6.00 MSP (15.000 Tons) Warhead: 0 Radiation Damage: 0 Manoeuvre Rating: 10
Speed: 25,000 km/s Fuel: 2,065 1st Stage Flight Time: 3 hours 1st Stage Range: 264.6m km
2nd Stage Flight Time: 93 seconds 2nd Stage Range: 5,208k km
Cost Per Missile: 12.1668 Development Cost: 1,217
Second Stage: Zhalo-IIIM x3
Second Stage Separation Range: 3,750,000 km
Chance to Hit: 1k km/s 250% 3k km/s 83.3% 5k km/s 50% 10k km/s 25.0%
Submunition (3x):
Zhalo-IIIM
Missile Size: 1.1500 MSP (2.87500 Tons) Warhead: 4 Radiation Damage: 4 Manoeuvre Rating: 19
Speed: 56,000 km/s Fuel: 230 Flight Time: 93 seconds Range: 5,208,000 km
Cost Per Missile: 2.8056 Development Cost: 281
Chance to Hit: 1k km/s 1064% 3k km/s 354.7% 5k km/s 212.8% 10k km/s 106.4%
This is a long range solution for sensor range of 200 mils.
Cruise stage:
Shkval-I
Missile Size: 6.0000 MSP (15.0000 Tons) Warhead: 0 Radiation Damage: 0 Manoeuver Rating: 10
Speed: 20,000 km/s Fuel: 1,000 Flight Time: 8,606 seconds Range: 172.13 Mkm
Second Stage: 4.0000 MSP
Cost Per Missile: 3.00000 Development Cost: 300
Chance to Hit: 1k km/s 200.0% 3k km/s 66.7% 5k km/s 40.0% 10k km/s 20.0% 20k km/s 10.0% 50k km/s 4.0% 100k km/s 2.0%
Submunition (4x):
Missile Size: 1.0000 MSP (2.5000 Tons) Warhead: 4 Radiation Damage: 4 Manoeuver Rating: 16
Speed: 50,000 km/s Fuel: 187 Flight Time: 101 seconds Range: 5.09 Mkm
Cost Per Missile: 2.36020 Development Cost: 236
Chance to Hit: 1k km/s 800.0% 3k km/s 266.7% 5k km/s 160.0% 10k km/s 80.0% 20k km/s 40.0% 50k km/s 16.0% 100k km/s 8.0%
This is a shorter range one (for about 120 mils sensor range), with more payload but slower cruise stage.
All in all you have to remember this is a specialized anti-fleet weapon and wont fulfill all roles like shooting down enemy FAC's or fighters, also is very inefficient if enemy doesnt rely on PD/AMM's at all and instead invests into armor/speed/ECM.
EDIT:
Also for the purpose of stationary defensive stations there is indeed a caveat that you have to move with your missiles to keep target highlited by sensors and this cant be easily resolved with having missiles on sensors. Since with new active sensor range mechanics extreme range sensors are becoming gigantic in size, you might want to have a hangar with a radar-equipped fast craft on your defence station to be able to highlight a target and a gigantic missile fire control on station to do the launch. So your extreme-range line of defence would be: see passive sensor contact on planetory tracking stations -> send recon fighter / FAC to highlight target -> launch the missiles from defense base.