And for the record I actually am a mouth breather. I discovered that from my dentist when I was a kid, but it makes sense. I'm actually being serious, lol.
That's what everyone says, and I know genetics are a major factor.
However, I had 2 clones of a strain, one of which I threw out to flower and the other I kept as a mother. The first one had good calyx to leaf ratio.
A month later I threw out the mother to flower, and the overall buds were way bigger because it was an older and bigger plant, the buds were also way leafier!
Keep in mind, 2 clones from the same mother, different calyx to leaf ratio. So even though it's largely genetic, there MUST be other factors that affect it.