Brad, don't use Tango it's not that vigorous or strong. Most of my Tango tree branches are skinny when compared to other mandarins I grow. But the Gold Nugget is a good one to use for interstock grafting. Gold Nugget grows fast (upward), strong branches and has many branches that are good sized, also gets a lot of fruit. I grafted my Sumo on sour orange, Gold Nugget, Kiyomi, lemon, Valentine pummelo, Cocktail grapefruit. Pretty much any mandarin,orange, grapefruit, pummelo interstock works fine. Just graft it on a variety that is as vigorous a grower as the Sumo.