I'm using pigeon bottles and teets with my twins. Ive noticed as the teets age they do leak more.
That being said T1 doesn't leak from the mouth but T2 does and it doesn't matter what teets/bottles I use. It's just the shape of his mouth. I hear your pain!
As a side note I've just bought the y teets and they are still pigeon but are made differently and T2 who leaks doesn't feed as well with them.