[time-nuts] Key to HP 106 Performance?

[Perry Sandeen]

Learned Gentlemen,
After TVB posted his HP 106 experience I became curios why it was so good after having a HP 107.
Both schematics look extremely similar but on closer examination the 106 uses a 2.5 MHz oscillator crystal which is doubled and then fed through a 5 MHz crystal.  The 107 uses a 5 MHz crystal but it is also fed through a 5 MHz crystal.
Both are physically mammoth compared to the previous 100 series which allows for more circuitry which makes both far easier to service.  Lifting however is another issue... 

Another similarity for both are the number of *factory select* with nominal values shown.
It would be quite interesting to know how they did the process of *final tuning*.
Regards,
Perrier