You don't need any angle on the torque converter if there's a drain plug in it - remove the cover on the front lower side of the bell housing - usually 2 small bolts. With a long screw driver, turn the engine over by pushing against the ring gear (ring gear is what the starter meshes). The drain plug is a 7/16 or 11 mm size, and undoing it will release about a litre and a half. If it's not there, then it's not the end of the world.
Was the copper seal for the band nut or the drain plug? The band nut usually has a built-in neoprene seal moulded in the thread.
