I bought a random crew neck men's tee shirt at Walmart. It fit perfectly. I looked it up online and bought two 3-packs. I may buy two more before all is said and done.

I'm top heavy so I don't like the cut of women's tee shirts. If I get it to fit across the chest it doesn't fit anywhere else and vice versa. With men's tee shirts, they hang straight down from the shoulder. No cinching in at the waist.