Damage type to protect against:
Guristas - Kinetic & Thermal
Serpentis - Kinetic & Thermal
Mordus - Kinetic & Thermal
Blood - EM & Thermal
Sansha - EM & Thermal
Angel - Kinetic, EM, Thermal & Explosive
Mercenary - Kinetic, EM, Thermal & Explosive
Rogue Drones - Kinetic, EM, Thermal & Explosive

Main Damage type to shoot at enemy NPC:
Guristas - Kinetic
Serpentis - Thermal
Mordus - Thermal & Kinetic
Blood - Thermal
Sansha - Thermal
Angel - Explosive
Mercenary - Thermal
Rogue Drones - Thermal

Jammers:
Caldari - Gravimetric = Spatial Destabilizer
Amarr - Radar = White Noise
Gallente - Magnetometric = Ion Field
Minmatarr - Ladar = Phase Inverter

Stacked module effectiveness:

1st module = 100,000%
2nd module = 86,9119842%
3rd module = 57,1037996%
4th module = 28,2469117%
5th module = 10,5988834%
6th module = 2,9989473%