Never do heavy defoliations unless you want to stress your plants and limit it potential health and yields.
Every leaf is a power factory that makes the energy to grow the flowers.
Less leaves = less energy being made = less potential growth..............it is that simple!
Also, buds do not need direct light to grow.
Light spectra we humans can not see actually penetrate upper leaves to strike lower leaves anyhow, making leaf removal pointless.
Buds are like fruit, they grow all over the plant, not just on the sunny side.
The leaves are also a vital resource of pre-made nutrients (carbs, sugars, amino acids etc) that your plant will draw upon during flowering, as it is more efficient to do this rather than make new growth elements (carbs, sugars, amino acids etc) and grow flowers at the same time.
This process of recycling is what is responsible for the stage commonly known as "the fade".
So, without the older leaves, not only do you reduce the plants ability to make energy, you also rob it of a vital reserve of growth elements it needs to use for flower development.
In forty years of growing, I am yet to see a plant that gets rid of its own perfectly healthy, green, energy producing leaves for no reason.
It is only people who think they know better than thousands of years of evolution that remove leaves from a plant that is at the pinnacle of efficiency and perfection.