The problem requires that Omega be always able to figure out what you do. If Omega can only figure out what you can do under a limited set of circumstances, you've changed one of the fundamental constraints of the problem.

You seem to be thinking of this as "the only time someone won't come to a decision fast enough is if they deliberately stall", which is sort of the reverse of fighting the hypothetical--you're deciding that an objection can't apply because the objection applies to an unlikely situation.

Suppose that in order to decide what to do, I simulate Omega in my head as one of the steps of the process? That is not intentionally delaying, but it still could result in halting problem considerations. Or do you just say that Omega doesn't give me the money if I try to simulate him?