Andy, I agree there is probably something out there that will work. Klotz's Coxoc has me thinking but it costs more than JD ether, so why? The AI temp of kerosene is 205-210 Celcius. Ether is the key ingredient to making it work always and well. I don't know what naphtha the engineering site refers to but some naphthas can be in the same range as gasoline. I think they have a typo because on the link at the bottom for flammable range naphthalene is in that place and and is something different and it does have a high AI temp.

Square one was to replace hard to find 20-25USD per gallon fuel with something that anyone could find and mix. The kerosene/DII/lube blend fits that for me even if I need to warm the engine on regular fuel. I picked up a fueler valve to make this easier.