I've found that with long cooks, the doneness often ends up one level more done than the temp would dictate on a traditional cooking method. In other words, 58C or 59C, which is right in the middle of "medium" tends to yield "medium well". Of course there is some factor played by the meat itself, but generally, when I want "Medium" I have to aim for the bottom end of the temp range or even a degree below. And, worst case, I can always cook it a bit longer in the sear to make the meat more well done, but I can't make well done meat more raw. This is just my experience and while I have calibrated the offset on my unit vs a known accurate thermometer, I haven't really investigated the phenomena that much to see if it's all cuts, or at what point in the cooking the meat passes from one doneness to another.
If you cut the roast up into steaks, you can shorten the cooking time considerably by bagging them individually, but the texture will be different. They will be more, well, like a steak, than like a slow cooked roast.