As a general matter, I've often found that smaller resorts may give you a better unit merely because you asked over the phone. I once called a small New Smyrna Beach resort, told them I had traded into their resort a week earlier, and asked them what unit I got. I was told that I had been matched up with a unit across a dirt roadway from the beach and not in an oceanfront building. They then looked to see whatever units might be available up front and put me into one of them. So a call never hurts.
Bigger resorts don't do that. I'm guessing the computer does the assigning...the assignments may actually be made a week or two before the week begins...and there's absolutely no guarantee about what unit you'll ultimately get assigned aside from unit size. But you can call and state your specific desires and they say they'll try to accommodate you. And in my case, perhaps miraculously, they have.
Those calls can't be made until they get that exchange information which may take up to a week. So I can't see how anything can be determined in a day.
