V3 is currently the one I am using. You can read a few posts to get the idea on the pros and cons of each variation.
Usually the discussion is whether V2 or V3 holds more potential.
Since, I am playing V3. I can give you some intel. V3 has amazing damage. You can either play V3 as pressure variation (but this will only do it till you reach higher ranks and ppl know the matchup and your style, then it will be ez punish for them) or as whiff punishing variation (In my opinion the idea of this char).
For both you should know his best footsies.
d4, really good low. You can dash on hit into standing 1.
f4, nice +6 on block advancing move, good to use after d4 on hit, to open up your mind games. (f3,4)
Standing 1, 9frames poke +2 on block.
B4, in my opinion one of the best, if not the best, sweep. -2 on block (thus basically possible still your turn).
B3, good and long reaching attack. Amazing after d4 on block.
D2, amazing long reaching uppercut.
As big boy Shao, you wanna play mid screenish (d4 on hit allows you that), meaty(b4, back-throw) or creating frametraps (F4 or 4, 4).
What leads us to best strings.
4,4 is plus 6 on block.
F2, 4 is plus 2 on block, long reaching, overhead. CON: it starts with a high.
f3,4 has 10 frames startup. THIS string is your best friend, you can cancel your specials out of it or can start your mindgames. It is somewhat a 50/50 since you can either cancel it into shoulder-charge or end the string with a throw (f3,4,throw). Be careful the throw will change sides, and the shoulder is ez to punish.
Also worth mentioning is ji2, 4,4 is +6 on block, therefore you can use it as you use f4 and spice things up. Keep the opponent knocked down and the pressure is real.
V3 stuff. I am not explaining the hole variation, there is a thread (
https://testyourmight.com/threads/3rd-variation-realm-destroyer-best-variation-post-aftermath-patch.73157/) you can read.
Takeaways: db1 breaks armor, good corner carry, amazing damage, ez to get punished on higher levels of play and most importantly db1 has a really nice brutality.
My goto online bnb is f3,4 xx bf3 mb, b3, b3, 4, db1. ~390 dmg 1 bar. (not optimal)
or
Corner: f3,4 xx bf3 mb, b3, b3, b3, 2,1, throw ~420 dmg 1 bar (cb potential)
Both combos are only executable if you are carring your opponent to the corner. Luckily v3 has a lot of corner carry. Basically, if you start the round with f4 on block (risky but possible) and while the opponent is mashing d1, you progress with f3,4.... you will end up in the corner with him, with him having 28% less hp and you in your comfort zone.
Worth mentioning: in the corner you can always take a breath and move half a screen away. That will let you stay in your kuddle zone and put a lot of pressure on your opponent since you can punish almost anything whiffing with b3 into 290 dmg(b3,b3,b3,2,1,throw).
That should help you, to get things rolling.