I don't know the exact calculations. However I've made a blueprint that produces 40.7MW of power consistently.
It has 6 boilers to consume the entire 60MW output, a tank to store enough steam to last through the night, and 7 steam turbines. Water input is at the bottom. It uses the max (546) heliostat mirrors for a single power tower, and is entirely contained within the mirror radius of the tower.
I just tested out different configurations in the editor using the time warp feature to see what worked.
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