! think that went really well! I liked it a lot better than the smaller space. They were a lot happier and it was less confrontational. You could especially tell Phoebe was much happier binkying away, and even Buster relaxed. He even managed to smell her head a few times without nipping. And honestly, his little nipping really isn't that bad, but that's mostly because Phoebe seems pretty laid back about it and doesn't seem to mind too much and doesn't react to it. If it did bug her, then there would probably be a problem. Even if the nipping doesn't completely go away, they can still bond. I have a bonded pair where the female is nippy and grumpy, but my male bun is very relaxed and laid back, and just puts up with it, and will just hop away from her. And yet even with my female being nippy to my male bun, I still feel he is the dominant bun, cause if he gets sick of her nipping, he'll box her a little, and she'll get scared and run away. So if Phoebe doesn't get bugged by Busters nipping, it should work out with them ok, just cause of her laid back personality.
You may want to include a 'neutral' litter box next time, just to avoid any accidents, as their dates are getting longer. But use something for the litter box, that doesn't have either of their scents on it, so no one claims it as theirs.