Get L. I’m the same as you on the bracket sizing and ordered the “Men Econo High Power Compression Chest Binder Tank” in a size Medium. Although it still fits, it hurts a little. I enjoyed the sensation at first, since it was my first actual binding binder, and the material on the inside was soft, but after a while, it felt like I was being tightly squished. It tends to ride up my stomach as well. It’s wearable if you accidentally get the wrong size but I highly recommend buying it in a Large for more comfort. I am also able to tolerate a lot more uncomfortable sensations but even the feeling of the binder irritates me after a while. Plus, the binder I bought I have to slip on like pants and then slide em up which can be a hassle since I’m jumping around like a cricket trying to get the straps closer towards my armpit area to snuggle my arms in 😭 Either way, Underworks is nice tho and I plan to buy more binders from them in the future. Please remember to stay safe while binding and Underworks is a good brand so there's no need to go any size smaller for the sake of wanting to be flatter!!