often seen in the street without a hat

I also haven't read either. I made a deliberate choice not to read Go Set a Watchman after reading that Lee was apparently not happy about publishing it and may have been coerced by unscrupulous publishers while she was elderly and vulnerable. I do intend to read The Testaments, but like you I feel like The Handmaid's Tale stands alone perfectly well, and ... maybe I'm just being cynical, but it does seem sliiiiiightly suspicious that Atwood decided she had another compelling story to tell in that same world at the same time as The Handmaid's Tale was being massively hyped because of the TV series. Far be it from me to begrudge a writer the ability to make a buttload of money, but it didn't really inspire me to read the book.