Ok…
A) 4500 seconds assumes you are down to 0 shield hp… in which case, if you aren’t competent enough to prevent that in hisec from npc rats, you just shouldn’t be playing Eve. 4500 seconds is an hour and fifteen minutes… if my calculator did the math right…
If anything, add shield-extenders and lose the specific resists, but keep 1 or 2 Adaptive Invulns… with the DCII it will give you all the resistance that will matter. Or, know your local rats and resist specific to them… no need for universal coverage.
First line of defense is, well, defense. Being a capital ship, technically, just the bare-bones HP across the board is enough for anyone to muster up the courage and time needed to fight of ~3 hisec rats. D R O N E S . they aren’t just for mining…
B) Why in Bob’s name are you fitting a cloaking device… at all…? Wormhole mining? Yeah, I’d understand, but this is hisec… we talkin 'bout hisec. -AI
Based on the simpleness of the question at hand (we all asked simple questions at one point, not placing blame) I doubt you are wormholing… so… lose the cloaking device.
C) When there is a massive invasion of 3 NPC hisec rats every 2 hours, after you have gallantly fought off the intruders, run the small/medium shield booster you will have placed on your ship to top off what should be about a ~90% shield HP.