</font><font color="blue" class="small">( I don't really see where that would make any difference during the start revolutions, whether the weather was warm or cold. Am I misunderstanding something here )</font>
Phil, You'r right on. Heat range of a plug is all about thermal conductivity. Poor conductivity means plug stays hot and can't dissipate heat to cylinder head = "hot heat range plug" The converse is true, also. On cold weather starts, when the fuel is atomized into a cold cylinder, the vapors want to re-condense into droplets because of the cold cylinder ambient. Even on the first few cranks with a "hot" plug, the tip of the plug gets hot enough to keep the fuel in vapor form in the micro-environment around the plug tip. Once that fuel is ignited, the wave of flame propagates to ignite the remaining fuel in the cylinder. Today's ignitions/plugs see voltages on the order of 10,000 - 30,000 Volts. With that amount of juice, it only takes a couple of cranks to heat up a "hot" plug, and more cranks to heat up a "cold" plug. Hence, the observation of more cranking needed to start an engine in winter if it is fitted with cold plugs. The other caveat is to keep the battery fully charged especially in winter. That way you can get the full measure of cold cranking amps into the plug tip.
Jack-- First off, thanks so much for taking the interest in our problem and working with us to help to solve it. I'm sure all of us appreciate your efforts. Like all my fellow PTers reporting here, mine has had the problem since day one, and now has nearly 60 hrs, and is still doing it. I will find a pair of the hotter plugs hopefully this weekend and give them a try.
