@Burntwire
First off, VERY NICE!! You are doing what Meyer showed in his patent diagrams. If you know what your looking for...he had a "wiper" arm on the negative leg of the bifilar choke. It is common practice to scrape some of the insulation off so a "wiper" arm can be used to effectively bypass turns on the "resonant charging choke".
What your pics show is you tuning in closer and closer to resonance. The huge spikes are not an "initial" spikes (the current dampens the Forward EMF spike)....they are "trailing" spikes, caused by the back EMF (the voltage is produced by the change in work over the change in time (Delta W/Delta T)....in this case change in work is the changing magnetic field...the change in time is how long it takes the field to collapse....as the off time/collapse becomes closer and closer to zero the voltage spike goes up)...the "bunch of little spikes" are the "ringing" oscillations which are tell-tale signs of resonant oscillations. Once you have hit the point where the large spikes are largest that is your "primary harmonic", there will be many harmonics that produce voltage spikes...but, the primary harmonic is the best one.
Again...great job you are on the right track
However, you will not see voltage step up until you address the charge leakage across the water gap...I suggest prolonged operation to build up layers on the SS tubes...the extra layers will help to get a more capacitor like action...This point is stressed by the Ravi replication that took months to "seed"