hmmm, typically off a veal cheek after braising you might be looking at a 4-6oz cheek, if your doing a tasting you are golden. But if you are wanting to offer a good 7oz portion of cheek, I would go for the beef. It has been a long time since I have braised cheeks, I would keep checking them and really catch them right when they start coming apart, any longer and you won't be getting clean portions and will be looking at ragu.
I always clean up my cheeks and give them a nice sear. As long as you take away that really tough strip (you will know the one) the rest should break down in cooking. I make a mirepoix, and saute it off with some beer or wine, reduce it down, throw some beef stock or demi in, and let it reduce for a bit.
I cool down my cheeks in the fridge, cool down my mirepoix/stock until its all gelatin in the pan. I always make sure everything is cold cold, then pack it all together in bags seal them up, 68 C for 3 days and you are golden, split each cheek into three pieces, they slice great out of the sous vide.
This is how I do mine, so I almost forget what they are like braised, I am thinking you should be able to lift them out of your braise, cool them, slice them, and reheat them in your braise for service. Hope this was helpful, oh they shouldn't take too long in a nice 275 oven, I would do them one day in advance though, so you can re-evaluate.