I don't know how many hours work Mears did for me
Pre-flight show time for an astro sortie was about 4 hours. The plotter pouring over his mystical tables compiling reams of pre-computed astro shots only, after a tech delay, to start over again.
Followed by more time double checking his work.
Then in the air doing a 5-shot (if you were lucky) or 7 if he was really trying, followed by more double checking his maths and mears all to end up with an idea of where you might have been 15 minutes before.