[Johnson] Matchbox knob positions

[K6JEK]

What are the correct positions for the knobs on Johnson Matchboxes?    
I'm resurrecting a KW matchbox and I really don't know what position  
the knobs should be on the shafts.  I imagine the left one has 0 as  
minimum capacitance and 100 as max.   But the right one, the one  
turning the dual differential capacitor, has me puzzled. The rotating  
plates can be meshed all the way on the bottom, all the way on the  
top or any amount in between on either side of center of the cap.

The manual is silent on this subject.

Jon