Hoppy:
  Thanks for your concern, I appreciate it.
  The resistors that I'm currently using are the 10K OHM ones, not 10ohm, nor, 10R.
As are shown in the induction heater circuit shown below.
  I would think that using the bigger heftier diodes, zeners, resistors, and caps that Akula uses, makes for a much better circuit. Although he does have three heat-sinks and fans, on all his fets and transistors. For a reason... and those three fans also consume some juice from the circuit.

Well, if people won't listen to my advice, which I have given about these circuits several times before, maybe when itsu and void are telling you the same things (use multiple poly film caps of the same value in parallel to make up the total cap value needed, use short heavy direct symmetrical wiring paths for all the tank circuitry (mosfet drain, capacitor bank, coil), apply ample gate drive voltage, clean signal to gate, have the Gate circuitry tight and symmetrical) folks will take _their_ advice and your heating problems will go away. I'm sure you have all seen my videos where I run essentially the same circuit, using the same P260 mosfets, for long times at high power without any overheating problems in the circuit. The loads I run can overheat since they are getting so much power throughput, but the driver circuit itself does not run excessively hot, if I use the proper capacitors. The Sprague orange drops are very good and I recommend them, however I have been able to fail a couple of them from overvolting, usually in the receiver part of the complete apparatus. Select poly film caps that are voltage rated at 10 to 20 times your supply voltage! Build up your capacitance value by using several lower-value, equal, caps in parallel.
I like to use 10 caps of 1/10 the desired final capacitance value, just because it is easy to do the math. For example if you need 100 nF, use 10 ea. 10 nF in parallel, all the same, all with at least 250 V rating.
Part of the mosfet-heating problem is reflected power from the tank circuit. This is the same problem that CBers and Hams encounter with antenna matching. If your SWR is high you will have lots of power reflected back into the output transistors and they will overheat. In these present circuits "Low SWR" translates into symmetrical output wiring, few interconnects, short and heavy conductors for the tank itself.

  Hoppy:
  I am following ALL the advice, even though not one of you has had any success to show for it. This means a self runner, which can be run 24/7, on 24v, (or NO battery), without over- heating issues.

  The schematic posted above, is showing that this same circuit can be run from 12v to 36v.  Using the SAME exact components that I have.
So, which is the part that I'm not following?

  The two fets were blown last year, not now, and have been replaced by the same exact fets. This while running on two dead 12v batteries. Imagine what two new 12v batteries would do. Heating issues are NOT resolved, nor have any of the suggestions made, make any difference on my circuit, as yet.
  I'm still waiting for my 18v zeners, to see IF there is any reduction in the overheating issue with the fets. Somehow, as MenofFather mentioned, fets are heating still even with the zeners that he used, in place.
   This circuit is an induction heater circuit, using 12v, 0.5 or 0.6 watt zeners for gate protection, as shown in the diagram. Neither the zeners, nor any of the 4 resistors, nor any of the tuning caps used are getting hot, at all. Nor is the feed back circuit getting hot or even warm NOW, as well. But, the Fets mounted on heat-sinks, with fans running would go up in smoke in a minute or two.
  I will however include bigger motherboard type of heat-sinks, and fans, in my next Akula build. As he has them on there, for a reason.