From the title it sounds a bit "Brave New World". This is from a couple of days ago, I effectively mastered sections 8 and 9. 8, no problems, although I got a little distracted by adding a line of a tune from a song in the 80s because it fitted (The Lion Sleeps Tonight).
9 was another matter, we were back to our old friend the crash, and his companion the frustration. This time I only(!) spent an hour and a half on it until I had to give up. Didn't you just know it though, only about 10 minutes after finishing I had a brainwave, the ultimate separation of Kontakt from any contact with things that might make it crash. Not just doing the Kontakt (and it was flute again incidentally) as a separate track, but doing it *without any processing*. Then I can import the audio "dry" mixdown into the project proper as an audio track, and apply the processing then. This is kind of what I've had to do sometimes when I have several guitar tracks using Guitar Rig, because the processor on my computer cannot cope with more than about 2 before it starts to stutter.
So I tried this the following morning, and in about 10 mins I was done. So general policy decision: if I have more than about 15 minutes of mixdown problems I will do this in future. So there!