Being a rep, I have to mention our product Katanadrol 2.0. It's a non-methylated PH that would definitely help you in making weight. I would probably use it the last 4 weeks leading up to your competition. This $hit will help you get ripped up. You could also throw in Helladrol, which would also add some lean mass to your frame before the competition.
Ideally, I would start these 3-4 weeks before your competition so that your last week on cycle would coincide with your comp. That way you'll have given the compound(s) enough time to kick in and you can reap the full benefits of them.
Now, taking my rep hat off, I can tell you IMO that clen/t3 will not do anything for strength, and may or may not do anything for stamina. T3 is highly catabolic and will cause you to lose a fair amount of muscle if you don't take it while on an anabolic.
You might also want to look into a SARM - either S4 or Ostarine. You can also stack both. Ostarine gives zero side effects even at high dosages...and the S4 can cause some vision sides if dosed too high.
There are also a lot of other natural supplements you can take as well to help out - but this is an anabolic discussion and I will leave it as such.