Others might chime in on this, but starting PCT 2 weeks before your competition sounds like a bad idea.
As far as carbs, I think it depends on how you react. I can get fairly shredded at 100-150g carbs per day, but I drop them down to about 40-50/day at about 1.5 months out with one carb up each week (150-200g). I take the extra calories out of my fat/protein so I'm still in a deficit.
I don't know much about diuretics. My opinion is that if you're in shape (not sure how lean you're trying to get since it's physique not BB) you can do fine with some sodium/water manipulation with a natural diuretic like dandelion root. I've used Xpel with decent results.
Do however much cardio you need to get into the shape you want. Those last few pounds will be a result of dialing your diet and finding just the right amount of cardio. Those last few days before the show are where everything can go wrong, so don't change anything if you're looking good!
Just my 2¢ but I hope it helps a little. Good luck, man!