If that happens, you should probably go closer to 50/50. If it holds up a little longer, then go to Mes outright.
But I think Hanigan needs to be catching Chapman every start, and Arroyo is probably going to ask for Hanigan as well. Homer also appeared to be a lot better when pitching to Hanigan last year.
That's going to be the tricky aspect. To make that switch, you're going to have to tell a pitcher that they don't get to pitch to the catcher they feel most comfortable with. Personally, I would have no qualms telling Bronson that Devin is his catcher from now on, because I don't think Arroyo needs a personal catcher, plus he can probably help Mes develop as a game caller a bit.