I've always found that if I call any time during the first day that passholder rates are released, I've been able to find availability at the resort I'm interested in.
Looking at the stress associated with calling every single morning at opening, compared with the savings I *might* lose out on by not calling immediately, I much prefer to lose the stress. (And so far it hasn't cost me anything, either. Once I had to stay at the Yacht Club instead of the Beach Club. If that were the worst thing to happen to me . . . .)