Originally Posted by garabandalg
I wonder if reading the long form of the St. Michael exorcism immediately before or immediately after the Warning would have any particular value beyond the usual value of such things?
I would not recommend that approach.
Instead, a thorough examination of conscience, followed by confession, days or even weeks before the Warning would be best. On the day of the Warning, let the Warning find you in sincere prayer about the sins of this world, and the sufferings caused by sin.