I agree with what Jimyra says about losing quality when storing and reheating "real" BBQ. Of course, the majority of your clientele won't have a clue as most of the places they probably eat at do it all the time. The problem arises because you will also attract those that know, and are serious, about BBQ and they will know the difference between fresh and reheated BBQ and this vocal minority could certainly ruin your reputation, making it known that you serve second rate BBQ. Where are you at? The reason I ask, is that I have found, in my many travels and lives, that people down South are much more tolerant of BBQ places running out of meat than those up North, were the expectation is that if you are open you have everything on your menu ready to go. If it were me, I'd follow the lead of those Southern places. Make what you think you can sell out that day and when you are out, you are out. It may be hard in the beginning as you may not be producing that much, but if your BBQ is good, and fresh, it won't take long for you to get a reputation and next thing you know, you will be killing it.
But even then you can expect some leftovers. Just find a way to repurpose them. I find that I am much more tolerant of reheated BBQ that isn't served to me as you would fresh BBQ. That means I am more tolerant of the pulled pork in a sandwich than I am of a pile of it sitting on my plate. In the first instance, because it is probably mixed with sauce I find it acceptable for it to be reheated, but if I order a plate of pulled pork it had better be fresh! Same with ribs. If I order a rack, it had better be fresh, but if you are using BBQ'd rib meat to top a baked potato I'm good with reheated stuff, although fresh is always better. Hopefully you get my point.