I may be way off base here, but I associate fatwood with long leaf pines. As for the make your own, I'm sure it would work. If I were doing it, I'd drill some small holes in the piece (1mm or less) to open the surface area, then bake the pine in an oven to get it really dry and hot, then I'd submerge it while hot in a mixture of hot wax cut with some mineral spirits or kerosene-- the thinking here is that as the air inside the wood structure cooled, it would have to draw some liquid into the structure.
a lot of work when you really get to it, but you are trying to make fatwood not just a fire starter. For that, I'd fill a small paper cup with dryer lint and pour enough wax in to wet the lint and then press out the excess by stacking up another cup. The edges of the cups light quickly and the lint/wax puck burns for about 5 minutes.