Are you talking about a vertical plug weld, or an overhead plug weld? Either way gravity is the enemy. On vertical plug weld focus on starting top center of the plug. Overhead setup is absolutely critical. You don’t want a large plug because by the time you get it filled molten metal will be falling on you. Over head you may have to do 2 or 3 short burst, hotter than what you would normally do. May not be the best way but that is how I would approach it, try and set up some test pieces to get the welder set up like you want it before you do it for real. That will save you grinding and filling holes burned thru. Another way of looking at it, more heat less metal. Reduce you wire speed to control amount of weld metal buildup. Good luck, Frank