If you don't fear deleting words you wrote, it's unlikely you'll be able to finish writing a good book. You're either be too paralyzed to write anything, or you'll write garbage (because all first drafts are garbage) and then be unwilling to revise it.
I don't think prose maps neatly to programming. With code, the endless abstraction features of the language make the ratio of LOC/# features very fungible and gaming the former often doesn't help the latter.
With prose, sure, the structure and outline of your book will affect its size, but my experience (60k words into a ~90k book) is that a certain amount of material takes a certain amount of words and you just have to work to get through them.
Writing is a marathon and it helps to have some mile markers.