For me, it depends on the content of the chapter. If it's a chapter focused on battles, I would estimate around 5-6 hours to write 5k-6k words, and maybe an hour to briefly scan through the chapter to make sure nothing is wrong with it. If it's a chapter that is about lore-building or explanations of things, then it takes maybe 4-5 hours to write 3k-4k words and then maybe another hour to revise and edit it for mistakes. If it's about development of relationships, then maybe 4-6 hours to write anywhere between 3k-5k words, then another hour or so of very small editing. When editing, I usually don't really focus too much on content, I normally edit for grammar issues and see if everything in the chapter makes a bit of sense... well at least that's how it is lately. Can't say too much about what it was like before.