the gai that fought madara opened the 6th gate fore long periods of time to put up with biju... He also opened the seventh 3 times and used hirudora 3 times.... He had colllapse 3 times he also fought biju, obito, madara, 7 swordsmen of mist, countless zetsu and so on... Clearly under 25% and yet he still almost killed a fresh juubidara.... So at 100% i am sure he can do significant damage to any nv shinobi