That's the problem I'm running into with having 2 books on the go at once. I'm flip-flopping between them at this stage far too often. I'm going to have to limit one to just notes, while pouring actual work into the other. With my recent inclination to work on BookB and the feel I've had for the characters, it's going into Primary mode for the next little while. We'll see how far I get.
Thankfully I've been keeping any sleep-interrupting work to point form notes. Oddly those notes seem to be more coherent when reviewed during waking hours than any "fully formed" ideas I'd written previously during those early morning sessions.
I'm trying a few writing exercises to try and put some sense of productivity into my what little writing time I have. More than anything, I'm spending the time writing, whether I feel particularly inspired or not, just to get myself into the habit of it. Some of it actually turns out well enough and may be usable, the rest I'll just consider time well spent increasing my typing speed and thought processes.
I've been informed that a good rule of thumb for your first submission to an editor or publisher should be over 150,000 and under 300,000 words. 300,000! Three Hundred Thousand! Bloody hell that's a lot of words! Here I am happy pushing out about 2500 a day, and not even achieving that every day.
It's going to take some really inspired writing to have to worry about going over the limit. I'll just focus on being over the minimum without cheap filler for the time being.