I would extend your diet to 16 wks. 12 wks can be done and many people do 12 wk diets, but 16 wks gives you enough room to get in shape and coast in. If anything goes wrong along the way, you will have a few wks to play with. I would shoot for being close to ready about 2-3 wks out and then take your time dialing in the last bit. I would start clen at 16 wks, using 40mcg to start and adding 20mcg every 2 wks, until you reach 100-120mcg and then stay at that dose for the remainder of the diet. I would start t3 at 12 wks out, at 25mcg and add 12.5mcg every 2-3 wks, going no higher than 75mcg. In the last 2 wks, I would start to back the dose down a little, as long as you are lean. t3 can make you go very flat. At the same time, it'll take some time for your natural production to come back, so I wouldn't come off until after the show. I would reduce the dose slowly until you feel that it isn't making you look flat anymore. Then after the show, use another could of wks to tapper off the t3. There is no need to tapper off clen. I would not use higher doses of t3 unless you are on gear. 25-37.5mcg would probably be ok without steroids, but above that, I'd be afraid of losing some muscle. 

Primo is a good drug for females. It's a little more aggressive than anavar. If you haven't used gear before, I would start with anavar, between 5-20mg ED for a 8 wk cycle. Start at the low and and see what you can handle. If you want to use the primo, 50mg 2x wk is what I would suggest.