How can I identify block quotes (indented on both sides) in text in a way that survives the compilation process?
I would use something like a text colour that could be easily bulk searched for in Word and acted upon. The Dark Green is probably a good candidate. This is the “old school” Scrivener way, but we’ve got better methods that will be implemented moving forward that will actually let you keep their original formatting as special, while still overriding other aspects (like the font), and completely cleaning up other text. Right now it’s all or nothing. Either no clean-up or total clean-up. The only real alternative is to split the quote out into its own document and then turn on Compile As-Is for it, but unless you only have a few quotes in your work, that might not be your preferred solution. It’s definitely workable though.
If you go the “no clean up” route–meaning, you don’t override formatting at all in compile, so everything compiles the way it looks in the binder–you might want to check out using script settings for this. The Undergraduate Humanities Essay template in the Non-Fiction category uses script settings to format the text in the editor, so you can take a look at how that’s set up for the idea. If you prefer to stay out of script mode, the Ctrl+T and Ctrl+Q shortcuts might come in handy to indent the first line of a paragraph and indent the rest of it for an overhang; adding Shift to the combo will decrease the indent.