I am wondering where the word count requirements originate. Is that an industry standard? Is it what you yourself have developed as the best structure? A mix of the two?
A mix of the two.
Word count is usually stipulated in the contract. In this case, my contract says 100,000 words, which is my natural length anyway. Legally I can go 10,000 words either side of that, so 90,000 to 110,000, although as I remember Fast Women was 116,000.
The act counts are mine because I write in acts to arc the plot. And because I want the plot to escalate, I try to make sure each act is shorter than the last one so that the turning points/big moments come faster together as the plot progresses. That’s just my thing, nothing contractural.