However, the second act is coming together, yay! And will help me substantially revise the first act. The point at which the writing becomes easiest for me is the end of the second act. By then I know all I need to know about my characters, all of the storylines are laid out, I just need to write the finale - I've been able to do the entire third act in two days before - and then retool the first act. There's always a lot of junk in the first act at that point; stories set up that I don't need, or holes where I need to set up a storyline. I also rewrite the beginning last, so that I've got a good grasp on my characters and how they'll play to the reader.
I found this nifty device that shows progress on a book:
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