So my Mylar bags came in and I've been busy stuffing my Esoterica Bags into them. At Woodsroad's suggestion I ordered .7mil gusseted food grade storage bags. Quite substantial shielding.
Of the Esoterica bags that I encased, only one showed signs of a pinhole. The rest seemed to be okay. One bag, however, had an issue of a different kind. It was a bag of Hastings that I had picked up in 2013 and it was almost completely dried out. The cause was a small slice, probably from a matte or box cutter, that had been made in the bag, one that I had missed in 2013, and since the bag had been sitting in a sealed bin all these years, I hadn't noticed it. The fact that the bin was sealed and pretty full possibly had something to do with the content not completely drying out. It's been rehydrated and jarred.