You can't make an educated pick until you've seen Mayweather at 160, which may happen at the end of his career. How would Mayweather handle such a big strong brawler? How would his power carry to 160? Stylistically Barkley should be easy to outbox, physically its a question mark
I don't know about PBF winning, but he would make it close. Barkley's own slowness would keep Floyd in it.