it has been a long time since the last time i tanked CT, but there's a reason for both strategies if i remember correctly, in terms of distance skeletons-dragon, pulling it far from the middle can be a mistake, it forces you to step in the poison and if 2 of them get close they will link, this can be deadly for some bad ptys, and they are easy to kill before the get to the middle, but in its last phase when you don't have to worry about the skeletons, some ppl tend to move a lot around the dragon and they en up eating some breaths, both ways are correct and no one is wrong but if you ask me i would say the most efficient way is tanking it in the middle and the last phase in an edge, and if there's a wrong way, that's stealing hate from the tank even if he's doing it in a weird position, as long as he's not turning the dragon it's ok.