ISO Fashion Advice - Whitesville Tshirt

Has anyone bought one of the viral Whitesville t-shirts and can speak to the shrinkage? I know it says to go one size up, but I'm usually between a men's/unisex medium and large. Given that, I'm not sure if I should go for a Large or XL. For reference, wearing a binder my bust measurements are just about 40in. I don't love super tight tops, but I also don't want to look like I'm swimming in it. Any tips before I drop the money for this shirt would be much appreciated - thank you!!