3 stage mine seems to be the way to go based on my understanding of missile mechanics.
Attached is my rudimentary minefield (still needs another few layers) established around a hostile JP using the mine below:
3rd Stage: Vengeance II Warhead
Missile Size: 14.0104 MSP (35.02600 Tons) Warhead: 15 Radiation Damage: 15 Manoeuvre Rating: 20
Speed: 22,169 km/s Fuel: 1 Flight Time: 0.7 seconds Range: 15,518 km
Active Sensor Strength: 0.2 EM Sensitivity Modifier: 8
Resolution: 100 Maximum Range vs 5000 ton object (or larger): 3,312,464 km
ECM Modifier: 10% ECCM Modifier: 10%
Cost Per Missile: 15.71 Development Cost: 1,571
Chance to Hit: 1k km/s 443.4% 3k km/s 147.8% 5k km/s 88.7% 10k km/s 44.3%
Materials Required
Corbomite 1
Tritanium 3.75
Boronide 0.12
Uridium 0.2
Gallicite 10.64
Fuel: 1
##################
2nd Stage: Vengeance II Missile
Missile Size: 15.5396 MSP (38.84900 Tons) Warhead: 0 Radiation Damage: 0 Manoeuvre Rating: 10
Speed: 42,228 km/s Fuel: 324 Flight Time: 3 minutes Range: 6.41m km
Active Sensor Strength: 0.2 EM Sensitivity Modifier: 8
Resolution: 100 Maximum Range vs 5000 ton object (or larger): 3,312,464 km
Cost Per Missile: 16.72 Development Cost: 1,672
Chance to Hit: 1k km/s 422.3% 3k km/s 140.8% 5k km/s 84.5% 10k km/s 42.2%
Materials Required
Boronide 0.12
Uridium 0.2
Gallicite 16.40
Fuel: 324
###############
1st Stage: Vengeance IIB Mine
Missile Size: 1 MSP (2.5 Tons) Warhead: 0 Radiation Damage: 0 Manoeuvre Rating: 10
Speed: 0 km/s Fuel: 150 Flight Time: 1 seconds Range: 0 km
Active Sensor Strength: 0.2 EM Sensitivity Modifier: 8
Resolution: 100 Maximum Range vs 5000 ton object (or larger): 3,312,464 km
Cost Per Missile: 0.32 Development Cost: 32
Chance to Hit: 1k km/s 0% 3k km/s 0% 5k km/s 0% 10k km/s 0%
Materials Required
Boronide 0.12
Uridium 0.2
Fuel: 150
In total, the above amount to a size 30 missile, which when deployed at a waypoint, lay in wait for an enemy and then trigger the 2nd stage. The 2nd stage closes range to the target and then the 3rd stage delivers the munition.