My toes hit the front of my boot while walking and standing. If i walk a lot it can cause a little discomfort. Once im on the board though and squatting a little, its totally gone and they fit like a glove. I wouldn't say my toes are curled while standing/walking though. If they're truly curled up, then i'd say that's too small.
If not are hitting the spot, i'd return them all and try a different brand/model.
Actually what you are describing is what I am feeling mostly... standing up its uncomfortable. Squatting a little on my toes, it feels fine. For you, when you lean back on your heel, was it also uncomfortable when you were breaking it in?