Being off estrogen, and with your bod producing testosterone again, is likely to have some impact on the size and shape of your breasts. Like you I stopped HRT after a while - I didn't have much breast development despite having been on HRT for 2 years. They weren't that noticeable so I never used binding to keep them hidden. I ended up losing a lot of weight about six months after I stopped and that made them shrink a fair bit but I always retained the initial mammary gland development. Anyway, yeah, they may shrink but it's unlikely they will go away altogether. Binding will effect the shape and firmness - I wouldn't recommend it, even if you think you'll never be back. I thought that too... even briefly considered surgery to remove the tiny bumps I still had. Soooo glad I didn't. It's a tough choice and really hard to know if you are making the right one. I'd suggest wearing a loose shirt over the top of a tight fitting singlet or tee.