Fcit,
I've been flying in different airlines crossing the alps and departing from northern Italy.
From my knowledge such documentation was prepared inside the company depending from the a/c type.
Drift down procedure is an alternative mean to the service ceiling requirements and has the same application.
Must meet:
1. drift down path (see net drift down path);
2. Vertical clearance;
3. Service ceiling at the airport used as alternate at least equal to the elevation + 1500ft.
4. fuel dumping permitted;
5. Critical points given as PreDeterminedPoint (PDP).
Cheers.
Fly safe & enjoy life.