Well this is what I think....when neji used the byakugan to fight hinata, remember when he cut off her chakra? If neji does his 360 to the sand, he could probably knock the sand down and then attack gaara with the divine strikes cutting his chakra preventing him from doing any other summons or attacks.
But from whats I've seen, Gaara has this on in the bag..I think he'd win..he is kazekage after all.
(of course we haven't see the "true neji") *suspenseful music plays*