Fair>WAFFLEcopter works for horizontal knockback
http://www.youtube.com/watch?v=0Rqxx74MclI
Unnecessarily long video but the part where GwJ actually survives makes it worth it
http://www.smashboards.com/showthread.php?t=241753
The thread behind it, where we figured that fair's little momentum-reduction is worth the extra 8 frames you wouldn't have if you airdodged>Side B
Edit: For vertical, Airdodge>Bair beats Airdodge>Wafflecopter ~Fail alert-->
by 1%<--End Fail alert: It's a lot more than 1%~ consistently when I fastfall the Bair by holding down the control stick(and 0% when I don't) Sudai knows his stuff. =P I'm trying Fair>Bair vs Fair>Wafflecopter now
Second Edit: I may be on to something here.
Fun facts so far: 1) Sudai doesn't know his stuff. I think my results are finding that Dair is BETTER than fair/side B for vertical knockback =P. I'm not done yet, but it's pretty interesting so far. 2) I'm testing this with Snake's uptilt which sends ROB up and a little behind Snake. Holding Down on the control stick makes ROB get star KO'd
faster than only holding down as soon as the aerial comes out (to fast-fall it), with any aerial. I feel like I should know this, but I'm not sure why, especially since I've always been told that holding the direction opposite the knockback (where the hit came from) didn't help you ("had no effect"). I don't think I ever heard that it hurts you.
Anyway, still going at this
Third Edit: Corrected some stuff and tried new stuff. Airdodge>Fair and Airdodge>Dair both destroy side-B when it comes to vertical momentum. Between the two aerials, they both beat out Airdodge>Bair and Airdodge>Nair. It turns out that they also both tie with each other and Airdodge>UPAIR. All three of them lasted until the same percent where I couldn't survive any longer, but to be honest, I felt that I was closest to surviving one percent higher with Airdodge>upair followed by Airdodge Dair. Both of them seemed easier to do anyway.
Of course, none of this actually matters because you can do aerials out of hitstun anyway and I know that upair obviously lets you live longer than airdodge>upair. I guess I'm hoping the relative efficiencies of each aerial will carry over without the airdodge, since there are a lot more possibilities now besides just fair>Bair vs fair>side B (SideB fails at saving you from going off the top. It works but it takes too long, unlike horizontal where its effectiveness is enough to make it the best choice compared to any other aerial after the fair**. Time to try fair>other aerials, dair>others and uair>others. Nobody really tested any of this out?
**Kind of like how Link's Dair is actually better in some cases (horizontal, similar to ROB's side B) even though it takes longer than around two of his Bairs. Even though it's slower, Dair does enough to help you whereas you can't do anything helpful after the Backair- you're still flying the same way.
Fourth Edit: I don't know if I can re-test other aerials>Side B for horizontal until I'm done with this, so if someone else can do that reliably, go ahead.
Fifth Edit: I'll be back in a bit- but I haven't found any combination of aerials to be more effective so far. You can fit 2.5 fairs in the same time as a little more than 1 upair on the largest stage before you die, but neither of them help/hurt any more than fair/Bair or even Bair>fair. I guess I'll try again when I get back. Oh, and Nair is horrible
--Meh, taking a shower and eating a banana pretty much ruined by DI/aerial mashing control. Maybe I'll keep going with this tomorrow.