T, if you could provide the basic tuning steps and put them in order of precedence, it would be most helpful for those who wish to replicate.  Extensive details are not needed at this time, just a simple outline.  For example, there are a couple of capacitors with unmarked values, how are those values found and what do we need to look for on the oscilloscope to find them.

At the moment, I'm not sure if given a completely finished device assembled by Ruslan himself, if I could actually get it tuned and operational.  The steps in tuning are probably more important than the actual hardware.

I will try again from https://www.youtube.com/watch?v=4DyLoXd4Ivk with some stuff in English:

The Grenade coil:
This is your waveguide and receiver antenna from radio electronics terms. The only difference is you are dealing with non-Hertzian waves and the SWR has to be maximum inside of grenade coil as opposed to conventional tuning.
 When you wind grenade coil, take measurement of wire, say, 37.5 meters, then wind layer on 50mm diameter tube until end for a coil length of 21 cm and return with second layer on same direction; then put wire up to the middle and wind layer to the opposite direction and to the end of tube and return to middle for getting 2nd two layers set; then again put wire across up to half of top layer; then do same with 3rth two layers set on half(1/4 of total) of top windings; the wire from the end of coil is put across to the begining inside of tube. The wire which starts coil goes to capacitor from yoke. The total coil is non-inductive and has very small inductance. The inductor is half wire length (18m) and on top of secondary  - the winding goes goes to the middle of tube then wire goes back across tube to begining and the second layer goes in same direction as 1st layer to the middle then wire is put across the tube to the beginning. The polarity must be find out on which way it works together with the secondary and Tesla coil.
The inductor is being driven by 1/100th wave harmonics.  The reason for 1/100th is getting driving frequency to bearable kilohertz range where ferrite yoke or toroid core is  working best.


The Tesla coil:
This is transmitter part and is tuned to the receiver as opposite to conventional tuning.
 The 0.7mm diameter isolated wire , the target wavelength must match quarter or half length of grenade coil (37.5 / 4 37.5 / 2). The wave peak voltage on top and peak amperage on bottom. When ground is attached it virtually extends the wire length and you need to  tune it again to match wavelength. Driven by sharp pulses from crossover pickup between voltage on grenade output coil and current on induction heater circuit. The resonant pulses go to top load and are matching wave. Few things to note - be careful not touching top capacitive load of Tesla coil as with thicker wire is makes much more current and can even knock you out unconscious! Also the CFL has to be fully lit when placed on table near top load.


The induction transformer:
The 26-28 turns coil is wound around with intentional space left for 3 turn coil which should have space between these two coils. Must be heavily isolated.
The 12+12 primary is on top of 48 turn coil in middle.

The tuning:
Forget about any LC resonances and spectrum analyzers, etc. You will be dealing with wave transmission system and only wire length should be taken as wave guide and everything is calculated from that standpoint. Same as Tesla and Kapanadze was doing.
If there is frequency mismatch - on the output you will see garbled and noisy signals which will indicate this situation. When you get to that situation you should extend or shorten wires. Avoid doing that on grenade coil itself because it will imbalance receiver. The tuning point is very precise and +/- 100kHz makes entire setup out of tune. The clean sine wave with sharp resonant peak (which is sine wave on quarter or half of 37.5m wavelength) is your target. The 15W bulb as load on grenade coil output should be good lit when running device from only from Tesla coil.
And you should realize effect as soon as it hits on right spot...


Hopefully this is helpful transcript.

Cheers!

Many thanks T.

Just a quick question:  Does the induction (toroid) transformer actually have a 48 turn secondary or 28 turn?

Sorry, my mistake, on 39:26 Ruslan said 26-28 turns

Regardless, I think the spec for +/- 100kHz is awfully generous; and I'll bet real world dictates probably something closer to +/- 10kHz, maybe less.

Get your wire length measuring devices calibrated boys, the secret is out.

The tuning point is very precise and +/- 100kHz makes entire setup out of tune. The clean sine wave with sharp resonant peak (which is sine wave on quarter or half of 37.5m wavelength) is your target. The 15W bulb as load on grenade coil output should be good lit when running device from only from Tesla coil.
And you should realize effect as soon as it hits on right spot...


Hopefully this is helpful transcript.

Cheers!

Yes, I've seen the 'effect' - a surprising and sudden increase in output efficiency - due to the push-push transistors being non-symmetrically switched, causing one FET to shut-down as previously reported by Batman.

  I'm glad that we can agree on something, even if it may be for the wrong reasons.
 

Please note that I deleted my agreement after you had modified your post. 

  Ok then. But, something other than stuck fets are the cause of such KW output levels, even if Ruslan's device is only actually outputting about 1.500 watts, or so, from what I see.  As a real 4000w output would light up that whole field, at night. And each bulb added dims the previous ones,
since they are sharing the same output power.  Or he is able to hit on a higher resonant peak, that allows for such increase in power levels.
  I aim to find out...  even if it's the last thing I do.

  Or he is able to hit on a higher resonant peak, that allows for such increase in power levels.
  I aim to find out...  even if it's the last thing I do.

How does he do that with just a touch from a 9V battery.