This is confirming what Bill told you in post #6 the 300V is practically shorted out when the spark fires so 25R at 300V is 12 Amps and it will continue until either the voltage clapses or something blows up.I've found that adding more resistance between the coil and the voltage doubler has eliminated the "filtering" problem and the circuit no longer destroys the inverters. However, I've come across another problem.
Adding resistors in-line with the circuit has proven to be problematic, as the resistors keep burning up. Anything below 420 or so ohms would work for a while without heating whatsoever (not warm to the touch), but then suddenly burn up. I wired a 60w light bulb in-line with the circuit and discovered why the resistors would suddenly fry. For some reason, something sets up a continuous arc instead of a quick spark.