Definitely use clen through the beginning of your PCT to help preserve gains while mitigating all those extra calories you'll still be eating. Otherwise, cortisol would eat away your gains and pack back on some fat.
T3 should really be reserved for during the cycle or in conjunction with Clen. Alone, its catabolic. You could honestly run clen through your whole 6 week PCT so long as every third week you dose keto or benadryl ED. While clen's anabolic properties haven't been proven in humans, people swear by it on longer cycles.
Take your temperature and BP often.