It was a bit of song and dance for the segment length. I started out letting it assign lengths to everything and then after certain changes it would come back and explain how it estimated any changes to the segment length and where I could trim/adjust to keep my total desired time.
I let Claude do a lot of the playthroughs to check quickly how strict the timing was compared to estimates and I would come in and validate that actual feel.
45s doesn't sound like a lot of time on paper but in the game itself it felt like an eternity at times. Lots of back and forth calibrating.