All my code does it turn on a port, wait a specified amount of time, then turns off that port. Open up the photovore_V1.c code, and replace the while loop to look like this:
servo_left(33); //modify this number to change center
delay_cycles(20000); //servos can only receive commands every ~10-20ms minimum
Compile and upload it, and you got yourself servo center code.
The exact time could be off a bit due to voltage differences, manufacturing differences, room temperature, etc. Also, I just guessed it when I did it - was too lazy to make it perfect