I understand the reasoning behind armouring a PP, but for an explorer I think it's wasted mass to haul around. I know exploring isn't all about jump range but how many exclusion zones do you hit that it's a consideration?
Rough landings on planets only do hull damage so as mentioned above a 1d repair isn't a bad call as you can synth limpets as required
Though as I said before it's your build so go with what works for you, I just found ot a curious mod for an explorer build and not something I personally would consider
Pp can start failing below 80%, and if you plan to do absurdly long journeys such as DW2 it might definitely help. Especially if you like to drink while flying. Dont forget that the loss in range would typically result in exactly zero more jumps on a 1000LY track.