On solar events: 1. Sounds like it would probably spare electronics, especially if not plugged in. 2. Sounds like it might or might not affect house wiring; those built or upgraded with the new AFCI breakers (recent changes to the US National Electric Code) sound more likely to be protected, if residents don’t flip their own breakers. 3. It’d be interesting to know how big an area could be affected and the size probability (both modern examples are far smaller than “hemisphere”), and whether it’s (as it seems, based on the two modern examples) more likely to come in though the poles. I.e., are Canada, Russia, and the Nordic countries more likely to feel the brunt? 4. Two known modern events, both in North America? I suspect there have been others, unnoticed, elsewhere. Think Antarctica would notice? The vastness of the Pacific? The depths of Russia? 5. It’s not entirely clear: how long do such events normally last? That might relate to how many satellites get knocked out. A full day would be a huge number of satellites.
Maybe the quoted values are from the equator? Maybe you can calculate the difference in solar radiation between the low 30’s latitudes and the equator, for that time of year? I agree with the general theme of some of the other commenters; it’s hard to believe none of them seem to work very consistently.