Jab is easier, grab is far superior.
From 0% dthrow > jab > dash jc grab > dthrow > jab > dash jc grab > whatever you want is legit until they DI away.
^^ very fast, you can often get a regrab before they remember to DI away.
Jab is good in some situations, but most I prefer regrab or techchase.
I say do jab there because unless they are at like 60+, you will have to react extremely fast. All the other DI you can watch long enough before making a decision. So just watch them DI for a split second and then regrab in all scenarios (DI away, no DI, little DI behind (to the point where you would have to dash)) except for when they do that DI. Then you turn around and do a late jab and try to tech chase from there. But I discovered something better today.
I got to play some friendlies with Gravy, and we tested some cool **** out. We did this with Falcon, but I'm sure it work with spacies too. If you dthrow and they DI behind you, buffer a turn around, wait for them to hit the ground, jab and then grab to cover tech in place and missed tech. We also tested whether you could react to a tech behind you, and it turns out that if you analog jump bair (I forget if you have to pivot or not, you might).....you still can't reliably cover that tech lolll. But you come so close, like the edge of the hitbox is literally touching falcon. But a lot of players probably will not expect you to try and cover three options like that, so it might work if they don't immediately shield. I wonder if the bair would hit Fox or Falco. I think since their techs are shorter it might, but someone will have to test it.
I also learned today that I fvucking suck at following up grabs against Falcon if they don't DI onto platforms. Gravy just kept avoiding the platforms and I missed opportunities to follow up. I think that in some situations where Falcon has to DI behind you off the uthrow to avoid the platform at certain percents (is it like 40 or something???) you can just turn around grab. But I kept ****ing that up because I would jc the grab and not turn around loll.
But one thing he showed me was the power of using pivots to tech chase Falcon. Pivot dsmash and wizard foot is a great way to tech chase Falcon as they will not expect you to change directions like that. It works very well.
Finally, (sorry for the wall of text guys, I'm only now starting to get this game so I have a lot to say haha) randy usmashes in neutral fvucking work against Falcon. It's hilarious. I also managed to do a reverse usmash to punish and kill a missed sweetspot. Sooooooo swaggg.