Nice to see the results match Dr Arthur Bradley, the OG in the field (no pun intended).

https://www.youtube.com/watch?v=aMct99DiZak

For my money, a triple burrito wrap of foil and ziploc gives 90+ dB attenuation plus moisture and mechanical protection.

Also nitpick, but the E1 pulse doesn't fry beefy transformers, instead it's the long-period E3 pulse (seconds to minutes) that raises the grid voltage and overvolts the transformers.