So, last chapter pretty much confirmed that the difference between Dojutsu and all other kekkei genkai is NOTHING, and all you need to use them is the chakra of someone who can use them, or be lucky, Since Kakashi is using Obito's MS with his own eyes, not implanted ones, because Obito is helping him.
So, when Obito was using his right eye and the Implanted eye, he should have been able to use Kamui with both eyes, Like Kakashi is now, Because he would have the Chakra of someone who can use Kamui, AKA Him.
So, when Obito was using his right eye and the Implanted eye, he should have been able to use Kamui with both eyes, Like Kakashi is now, Because he would have the Chakra of someone who can use Kamui, AKA Him.