Getting thousands of points in that game was no big deal for me since I played it more than pretty much anything (bought all the items on that moogle's list, some multiple times). My only complaint about it is that I could reach the max amount of items you're allowed to find per game (8 I think it was) really fast in the ocean cave, but in the sky garden I hardly ever got more than 5 or 6 since it took too much time to run back and forth between the two floating islands. On that note I would think it would be best to stay at the cave to search for the sword if you want it since overall you could get a lot more chances in finding it even if the odds are slightly higher for the sky garden.