a) don't make things more complcated than they are: if you see the pitch knob as a clock, it is normal that you have to turn it one hour clockwise for each 3 to 4 degrees Celsius/5 to 7 degrees Fahrenheit increase of the ambient temperature.
b) don't risk to mess up your pitch field by adjusting L5. A simple slight correction of L6 will do the job. If the slug has a hexagonal hole, it will need about 1/12 turn counterclockwise in order to bring the pitch knob back to the center position, while the older coils with a normal slot have to be turned the same amount, clockwise.