herbacache

The Pocket Queries sound like the best way to create a 'hit list' for travel. I'm using a Garmin 64st and was about to create my first pocket query then realized the unit comes with 250k caches already. I don't want to duplicate caches that already exist, so have hit a bit of a wall in trying to find the easiest way to identify caches I don't already have. Does anyone have experience with this scenario?