I like to use Nair more once they have some percentage. It does more damage and has more knockback than Fair and I'm pretty sure it has a little bit more range which is helpful when he's coming at you with the same attack. Good combos with the Fair tho. One thing that might be worth trying while edgegaurding, is if you're on the ledge while they are recovering from a lower angle, try ledgehopping a Bair. It has great knockback and you still have plenty of time to recover. Nair is also a really great edgegaurding technique, because it has more knockback than Fair. Either run or jump off the edge facing them and do a Nair, then if you need to and they aren't too far away you can double jump and hit them again with a Fair before you upB back to the stage.