Here's another "plug tutorial", seems there is some differing philosphies or down right misinfo sprinkled about the web. I just found this
jem from the early days, when I got my first whiff of glow fuel. (plastic yellow TriPacer U-control, powered by the "mighty OK cub" , under the Christmas Tree, 1959) "Cold plug" is just as it seems, sure, there is less methanol with High Nitro, but the use of a cold plug in this case retards the ignition point. (it is probably heavier wire, but for shock resistance in a severe racing app. not heavier wire to boost the ignition probability for lack of methanol content)

http://www.iroquois.free-online.co.uk/gloplug.htm