Wish I had seen this earlier. I purposely try to finish a few hours before serving. If you wrap in foil and a towel then put it in a cooler it will hold for hours. I inadvertently left one for 8 hours like this and when I checked for temp it was still in the 160's. We'll above the danger zone for food.I put it in the fridge already. Should have shredded it before that like you said. But will take it out around 3pm and heat it back up, maybe with some beef stock in the pan to keep it moist. Hopefully that does the trick. Not to worried.
Doing a Sou vide later on with some tenderloin using my electric HLT. Never done that before. But at least if one of the two doesn't turn out right the other likely will!
I'm sure it will reheat well. I usually use some apple juice with a little rub added to reheat.