50mcg you won't have any sides or strength loss. You can actually use that dose to bulk. 75 for cutting. With tren in the mix you can really abuse t3 with out muscle loss just the sides become hard and not worth it. You also become flat and can't get a pump when you train. If you do this takes about 7 days of lowering the dose or stopping it until you fill back out. You seem to have everything in line though so 50-75 and you will like it