I think the reference to a "real induction heater" was just a bad choice of words.
You have definitely constructed real and very functional induction heaters - impressively so, from my point of view!
The debate is only about how the FETs are driven. You know the frequency it's running at & stated it earlier, about 60 KHz.
If you drove the FET gates with an external oscillator at that frequency and added proper gate drivers, as you would use for the lower half of an H-Bridge and with non-overlap timing so each FET is allowed time to turn off before the opposite one turns, the overall efficiency should be much higher and heat dissipation much lower.
That would also avoid all the problems with the choke setup, as that should then be far less critical, if it's needed at all.
As it is, each FET only turns off _after_ the opposite one starts to turn on, so they are fighting each other and producing high current spikes, which require the choke to keep under control. There is a lot of wasted power in that configuration.
In principle, you would be converting it to a push-pull switch mode PSU like this -
But without the transformer secondary or any feedback, as the heating load itself becomes the secondary of the coil/transformer when that is put in the power coil..
Edit - oops.. wrong thread, I just saw the tail end about the "real" comments...