I doubt it. The reason being amaratsu and sanusoo (forgive the typos. I don't remember how it is spelt) are used by two different eyes in the same person. Probably works the same way.
Aye, I thought the same. But after seing all the links (The same swirl animation, the same dimension) I've come to the conclusion, the only real difference, is that kakashi uses it on long distance, and Tobi uses it at close range.
And I also think that's one of the reasons he can do it so much without using all his chakra (and ofc. bacause of the fact that he might have Senju dna etc.). Because he's only transporting parts of himself, and rarely transporting other persons, and always at close range - So I think the distance to the object also affects the chackra consumption