Rotary/stationary gaps


A rotor with 12 electrodes is also a VERY good idea, as 12 has
lots of multiples so you can remove 2,6,8,9 or 10 electrodes and
still have the remaining ones evenly spaced for a 12,6,4,3, or 2

No you cant remove just two! 
You know what they say about 
too much RF.........   :)