So...
I messed around with this for about 20 minutes yesterday. I couldn't really get the lock to work more then 2-3 times using just the air. That said, I use to always hate it when a character stood right next to me because I wouldn't know how best to react. The best example here is MK after he does a Tornado: if he lands on top of you there is no really ideal reaction...that is until I started using this **** and instead of going for the lock just glide tossing for regular followups (so MK lands on top of you, you short hop single nana D-throw > D-Air > glide toss follow up/whatever).
I don't think the single banana lock is the definitive solution as far as Mach Tornado follow-ups go. It's my second favorite move to bait and shield with a banana peel in hand. The only other move that is easy and excellent to bait in Meta Knight's arsenal is his D-smash, because a D-smash that's blocked on either side of him will re-space you enough to where you won't miss a glide-toss followup in either direction. MK mains obviously go for this move at a disturbingly high frequency (more so than the Mach Tornado once they discover how badly the cool-down frames on the move will get them murdered), so once you establish a read for when and where MKs execute this move, it will be game over.
I will say that I have had difficulty properly punishing Mach Tornado in the past (MKs unfamiliar with being punished severely by cool-down lag won't even try to retreat the tornado after it fails to shield-stab), but that mostly occurred when I wasn't being mindful of my position and would actually glide-toss forward
past Meta Knight. Even at that though, followup options do exist in the form of standing still and just throwing the banana, D-tilting, jab-canceling into a D-tilt, or grabs/dash grabs.
But as I mentioned, the single banana lock is a welcome expansion to those options.
Also, the edge spike is sick. I'm hoping this will be the solution to my Pit edge camping problems.
While we're on the subject, I came up with a semi-unique setup similar to this; it involves banana-locking an opponent towards the end of the stage, but right before you chuck the last banana to send them over the corner into an edge-hug, you follow their DI backward with a dash, and then Z-drop a banana on top of them to send them over the edge and follow up with a D-air spike. Not as flashy, but it's a great deal easier to execute. =)
But like I said: mo' options, mo betta.
KRDsonic is going to upload it. You could also upload it if you don't feel like waiting for him lol.
I'm in Dallas 'til tomorrow and I don't have access to my recording resources. I'll do it if KRDS hasn't done it by tomorrow night, but hopefully he beats me to it. =)