Stacking Penalities
1st mod: c(1) = 100,000% effectiveness
2nd mod: c(2) = 86,9119842% effectiveness
3d mod: c(3) = 57,1037996% effectiveness
4th mod: c(4) = 28,2469117% effectiveness
5th mod: c(5) = 10,5988834% effectiveness
6th mod: c(6) = 2,9989473% effectiveness
7th mod: c(7) = 0,5134081% effectiveness
8th mod: c(8) = 0,210

Enemies-Hardener to use-Damage type to use
Blood Raider-EM/Thermal-EM
Guristas-Kinetic/Thermal-Kinetic
Sanshas-EM/Thermal-EM
Serpentis-Thermal/Kinetic-Kinetic
Angel-All Resis (pri. Expl. ,Kin.)-Explosive
Mordus-Kinetic/Thermal-Kinetic
Rogue Drones-All Resis (pri. Expl. kin)-EM
Mercenary-All Resis (pri. EM, Therm)-Thermal
Amarr-EM-Thermal

Hideaway<Burrow<Refuge<Den<Yard<Rally Point<Port<Hub<Haven<Sanctum
Normal<Hidden<Forsaken<Forlorn