Hi Chuck, you might find more success if you turn the bulb inside out, so to speak, with the bulb being where the gap would be with the plug it replaced, as you say, about ten to fifteen thousandths thick, definitely rounded, and with the worst heat path possible to the threads, and perhaps a small plug that can be inserted once the engine runs, to close the opening of the bulb you use to heat it, so it won't lose heat to air convection. The hot bulb setup is essentially the forerunner to the glow plug idea, before tungsten wire was available, which will glow long, without burning away soon. I would consider turning a bulb of stainless, as it holds heat well, and doesn't conduct well, a bit smaller than the shell of a cm-6 plug, then turn the rolled shoulder of a plug which holds the ceramic into the plug, allowing you to remove it, and have a "shell" with threads, but with some air clearance between the outside of the bulb, and the inside of the part of the plug which is threaded, with the bulb protruding as far as is reasonable, into the combustion chamber, and with the connection to the plug "shell" at the far outside so heat has the longest to travel to get to the shell by conduction. I would either tig weld it at that juncture, or absent tig, I would braze it using silicon bronze rod, with the tig being preferable as it would allow using stainless rod which is again, a poor heat conductor. The bulb would only need be of similar size to the center electrode of the former plug, but sticking past the end of the threads would help it get enough heat to stay hot enough. Ultimately, the timing issue is best controlled by the compression, as it's effect on the temperature of the mixture is all you have control of, with regard to the ignition, once the bulb is hot. The earliest iterations used continuous heat on the tube or bulb, but it was figured out soon enough that with the proper placement, the heat of combustion would keep it hot, but requiring a firing on every stroke, and no "hit or miss", as that would allow the bulb to cool completely. Having a "tit" on the very inner tip would do no harm either, and leave a point for the heat to remain concentrated. ttfn, Jack