Have you thought of doing a cage within a cage? I know that separating the two and then putting her cage in his seems like it defeats the purpose, but perhaps she will be calmer since she can sit next to him. And because you've got a double-wired cage (you said you wrapped the original cage in mesh), it will probably be harder for him to breed her from outside of her cage, if at all. If that works you could move the cage JUST outside of his after a day or two, so that they're still next to each other, and then slowly move them farther apart so that there's no chance of his penis reaching her.
I know that with larger animals neutering can change their personality, but I don't think that is an issue with smaller animals. I would keep asking around, but I can imagine that you would be able to neuter Jozy and his personality will be the same.