Training for tournament(help requested)

As it happens, there’s going to be a local tournament near me in a few days, and since it’s the first one, I want to enter even though I haven’t played basically since the release of Ultra(except a few rather casual matches against some people I know will be entering as well).
I have a solid understanding of general fighting game theory since I play quite some(GG, BB, Tekken, UMVC3, Skullgirls, etc), I also had about 1k matches online at least, back in AE.

What would be the most effective use of my training/research time until the tournament, that would result in optimized skill increase? I mostly played Ryu, Juri and Akuma back then. Since I’ll be relying on neutral a lot this time, I think it would be really bad not to have a DP, so Juri is out. I guess I’ll pick either Ryu or Akuma, then only train that one.

As I always played more games that had cancelling in them, I always struggled with SF combos other than a simple jump normal > ground normal > special. I never really trained FADC into ultra(and honestly, I don’t think that’s the one game changing thing for me right now).

It’s more or less obvious that I probably won’t win the tournament, but I really want to give the people I play there a surprise and make them sweat a bit for the win.
Given these factors, what should I focus on? Finding some short, reliable combos for the common situations(big punish, anti-air, my/their wakeup options), trying some setplay against the character I know they use a lot, maybe learn some new skill that’s doesn’t take long to consistently execute, but can be crucial?

Sadly the only obvious suggestion I would give myself(to just go and actually play some games) is out of the question, as currently I don’t have a subscription, so I’m restricted to training mode.
Thanks for any useful advice^^