although i don't use a heat press, i would stick to higher quality stuff. I would have to suggest hanes i guess. The anvil tees seem a little thin to me and they shrink substantially especially because the 100% cotton thing... shrinkage is always a factor with cotton. I would say gildan has some sturdy tees too, but they seem kinda wide as the sizes increase.. i'm just picky i guess.
hope that helps some!
hope that helps some!