When Sasuke's chidori goes from pierceing a rock to destroying a meteor means something.. It could possible means that his chakra has grown much more stronger and powerful, so to say Sasuke can't use humanoid Susanoo again is just speculating.. And off course he has Petra path to take chakra from his opponent is another way to allow him to use humanoid Susanoo again.. About Sasuke using Kurama's chakra, yes he did. But we all know that Kurama's chakra is much stronger when synced whit his Jin, and that's what made Naruto's resengan match the Enton chidori..
As for who is stronger? Naruto was stronger at 699. 700 and beyond, I think they are equal.. Like I said before, with a fully mastered rinnengan, Sasuke has a counter for everything in Naruto's arsenal.