Yes, I carry OWB all year round. Being in FL, most of the time I just wear a loose fitting t-shirt. When it's cool enough, I will just wear a regular size t-shirt and wear a loose fitting button up shirt (unbuttoned) over it or one of my bodyguard jackets: Israeli Secret Service (SHABAK) Bodyguard Jacket
It really doesn't take much to conceal / prevent printing.
If I ever do have a problem with printing, I use Heat-N-Bond Iron-On Adhesive, which lets you attach of piece of material to another without sewing. So I can add a layer to the inside of a shirt just in the area where it prints and then I don't have to wear a heavier shirt.