You want to be VERY accustomed to the length of your aerial down-B so you can space it with utmost precision. spider_sense and i have played so many dittos that I have really gotten good at keeping my down-B's safe. Baiting someone is all about being more familiar with "the line of safety" than your opponent is. When I played RockCrock a few months ago, he knocked me far and high offstage with with a fair. Instead of jumping toward stage and down-B'ing, I jumped BACKWARDS and down-B'd. I was in the magnifying glass (or close) and he didn't see that I jumped backwards, he just thought I jumped forward. So he hard commits to an offstage fair, but I am nowhere near it. He actually said "WTF" out loud. If you understand effective range of moves and judge distances better than your opponent, you can do something that is just BARELY safe, and since your knowledge > your opponent's knowledge, he may falsely interpret the move as punishable and commit to something that is guaranteed to whiff. This knowledge comes from grinding situations. It's better to grind situations than to just play. Pretty sure (regarding this specific situation) with 20XX you could restart a recovery/edgeguarding situation over and over, experimenting with your limited options. I say limited, but spacing changes everything. You would increase your knowledge of the length of the down-B immensely. You could work on teching and meteor cancels too. Remember, in this case being safe from fair or moonwalk offstage hullhop +dj reverse uair isn't enough, Ganon can also dashjump (fullhop) into dj up-B you, which reaches farthest.
But yeah, being able to snap to ledge after a precisely spaced down-B is useful. You also want to be able to down-B then dj to ledge every time too.