I'm a bfc with NCT, lovinit.
Yes, full breasts have more milk in them than soft breasts - but not all that much more. When breasts are full for a long(er) time, they send a message to the body 'stop making more milk'. This is done via the Feedback Inhibitor of Lactation, which is a protein. Unremoved milk accumulates this protein, so the longer breasts are left with more milk in them, the less milk is made. The converse is true.
Over time, leaving the breasts with milk unremoved, means the milk dwindles away.
Short gaps between feeds = more milk.
Long gaps between feeds = less milk.
It is all pro rata, but complicated by the fact that mothers' storage capacities differ (nothing to do with the size of the breasts, BTW). A mother with a small storage capacity and a baby with a large appetite will need to feed her baby more often, to make more milk, whereas a mother with a larger storage capacity and a baby with a smaller appetite will need to feed less often.
Add to this the fact that the less milk there is in the breast, the creamier it is.
So it makes absolutely no sense at all to feed according to the clock, either for frrequency or length of feed. Every mother and baby is a unique partnership and the only way to go (until bf is well-established, whch can take a variable amount of time) is to follow the baby's lead and stop trying to regulate it because you risk not having enough milk
Hope you are not now all blinded with science!