Shields come stock with a -20% penalty to thermal weapons, +40% to Kinetic weapons and +50% verse explosive damage. Thermal weapons are the biggest weakness and by engineering the shields for thermal you are actually making them harder to punch through than just going for the reinforced more shield points route. Engineering the shields is the first step. The next step is using shield boosters to moderate each of the categories so they are not so drastic. If you have a bunch of utility spots its easier to tailor them. I focused here on getting my kinetic back to above stock. Then I went for pushing the Thermal and Explosive up as far as I could before I ran out of materials. I last longer and can take more of a beating since lasers and missiles are losing 60% of their punch.