Let’s think before we do. I don’t recall your cooker, but most fat down guys are pelletheads. Because the majority of pellet machines have a central pot (mine doesn’t) but if you have two racks and can place a pan under to catch drippings then that will deflect the heat enough. If cooking directly over coals or heat source it can be an. Issue as fat down or up. I try hard to run fat side up. In the end don’t be afraid to smoke for a few hours then place in a pan uncovered to finish the cook and catch the juices, this can be very useful with flat only or lean brisket. You have plenty of cooking experience. Just follow your common sense here. I know it will be good and I’m pulling for you.Well with my screwed up trim job it will definitely be no fat side either way. One post mentioned taking some of the fat I cut away and lay on the thin edges. I’m going to put some of the meat and fat in a pan underneath it as well.