If you use GeoGet, this task is pretty simple:
Decide, if you want to copy the whole database or it's part. PocketDrake is tested on more than 20 000 caches.
In the case, you want to copy only part of database, perform these steps:
filter out caches in GeoGet and export list as GeoGet GPX v2
create new database named for example PocketDrake
Import GPX from step I. to new database
Copy prepared database (the whole geoget.db3 or selection from previous step) to your device, default folder is /sdcard/adrake.
Run a:Drake and select database in Settings.
Done.
Although the database of a:Drake is the same as the database of GeoGet, it's not recommend to overwrite the original database from the GeoGet by database of a:Drake!
a:Drake can directly import GPX (standard GPX by Groundspeak, no extra extensions). Import is suposed for quick load of new caches, massive load of data should be done via GeoGet.