Although the error-corrected version of my project was delivered by OSH Park a couple months ago, life intervened and delayed progress.
Following the typical order of operation for assembling a small board such as the ZeroCool, I first soldered the smallest devices to the PCB. This includes the passives, the FET, and then the opto. After I salvaging the MCU from the test Rev A board, the micro and the solderless terminals were affixed using hot air.
With an early version of the Rev A firmware still resident on the micro controller, I connected the temperature sensor and fan to the board via their respective terminals. 5V was then applied to the board. Expected behavior was observed; adjusting the bias trimpot resulted in a fan speed change.
Next steps: reprogram the MCU with a more recent firmware that corrects an audible fan whine by moving the PWM frequency outside the audible range.