I'll pass on the sulphur, trying to quit
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What I had read refers to "wide cut" as in the distillation process, you start at the bottom with the heavier fluids, like bitumous tar and bunker oil, then work on up through the heavier stuff, and the JP4 came out of the distillation process somewhere between gasoline and kerosene/diesel fuel. They thought it would be more readily available in time of war, ie it's not gasoline, so not taking away from gasoline production, and not diesel fuel.
Gilly