It's a simple process though. Not only does Byakugan allow him to perceive better, but it allows him to distribute his chakra perfectly. Neji would easily be able to calculate how much % of chakra was needed to perform Rotation, stop it, then successfully combo in 64 palms.When has Neji ever used the two techniques back to back that quickly? I don't think he'd be able to jump the gap and complete 64 palms before hidan just jumps backwards.
I strongly believe Neji is much faster than Hidan even in Pt.1 due to this scan Draegod linked me awhile back:
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The impressive feat here is that Neji on his deathbed blitzed that distance before Kidomaru could fall, and touch the ground. And it literally only takes 1-2 seconds to hit the ground, from where Kidomaru was:
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Neji literally blitzed easily 50+ meters in a second.