>I don't buy into the putting it on top so the meat is basted by it, I don't think it "melts"
>and flows through the meat, that also leaves the meat side to spritz or mop.
The purpose of basting is not to have fat or liquid flow through the meat - that can't happen - it's to keep the surface from drying out. I usually cooked my brisket fat up but last week I tried it fat down. After about 6 hours I checked on it and noticed the sides were drying out badly. So I flipped it over and the fat started dripping down and moistened the sides. I'm pretty sure if I left it down the full 12 hours that it took, the sides would have turned out too dry. Of course YMMV depending on your setup. Some cookers have high radiant heat on the bottom, so cooking fat down might be better. The Memphis has pretty even heat, so fat up seems to work better. It's really best to try it both ways, several times, and draw your own conclusions.