My friend already has TGD on his bookshelf, unread as yet, so I'm following this thread with attention but not taking any action based on it.

There were no rules agreed - just sympathetic reading, and some kind of follow-up afterwards. We're both fairly conscientious - our acquaintance goes back to belonging to an online book study group a few years back, so there's sort of a tacit agreement that while this is a back-burner project, we're being deliberate about it.