You know Obito can only use double kamui if he uses kamui while someone else uses kamui on him? He cant use both kamui types on himself by himself at once. Although Madara used "kakashi" eye the way Obito uses kamui.. -thinking- so Obito probably could use both eyes the way he uses "his" kamui..., but he still can't use them both MS jutsu simultaneously .. since you can't activate both MS eye jutsu at the exact same time. Like Itachi can't use Amateratsu & Tsukuyomi simultaneously.. -thinking- Sasuke's amateratsu & enton though... ms to ems is different...
ot: idk