Do it, then announce it. Don’t give them a heads up.
Part of why they’re releasing things this way (i.e. giving a day or two between declassifying and actually releasing the information) is to expose the media. Give them a few days to tell the public that whatever info is coming out will not be incriminating, then reveal them for the liars they are once the info is released. This is a technique that Andrew Breitbart used to great effect when he and James O’Keefe exposed ACORN.