T3 is one of the most harmless cutting suppliments there are out there. There is massive evidence of people overdosing it heavily (300 mcg ed for years on end) and then going off it and their thyroid bumping back to normal in just a few days. Bodybuilders inject so much shit in their body that t3 is one of the least harmful things you can put in you. I'd say a must if you're cutting. If you're already injecting compounds or taking clen that is also anti catabolic, no reason why to not go on t3 aswell. If you don't believe me just do some basic research on the subject yourself instead of listening to hearsay from a bunch of bodybuilders on forums.
Clen will be individual and alot dependant on what product you use, loads of info on it online already so wont go deeper into it.
T3, 50 mcg gets the job done for most people, maybe 75-100 mcg ed if you're really desperate, but be aware cause the catabolic properties of t3 can eat away at your muscle tissue at high doses (regardless of AAS)
Edit:
Don't run T3 without clen, as it will just eat away at your mucsle tissue
Don't run clen without t3, if you're already putting clen into your system t3 is harmless in perspective. T3 has never killed anyone, clen has. Or a combination of clen and other substances i should say.