I would never suggest t3 or any form of clen while on a fat burning cycle. If you are eating a fairly clean bodybuilding diet, any fat that you gain in the off season is from taking in more cals than your body can use. Using a fat burner is just going to burn off some of the cals. It'd be more logically to just reduce the food by a small amount, if you are getting too fat. Some fat gain is to be expected in the off season, but that doesn't mean you have to be a bloated mess. You can stay pretty lean while adding mass. I usually start at around 7-8% and never go much past 11-12% at the most, in the depth of my off season. 

I would also strongly suggest that you do not attempt to use any form of fat burners in PCT, nor would I suggest that you try to get lean during that time. Getting lean requires eating less cals than your body needs to maintain it's weight. Muscle is the first thing your body wants to let go. Muscle requires a lot more cals than fat to be maintained, so your body looks at losing muscle as an easy way to become more economical. IME, You'll be extra sensitive to losing muscle that you have recently gained on the cycle once you no longer have the hormonal support that it took to grow. 

You have to take your time with this and look at the sport in phases. Take time to grow while not getting overly fat and then after you have gone through PCT and taken the proper time off gear, consider doing a cutting cycle to work on maintaining the muscle you have while getting ripped.