Have you thought about taking off those lower branches maybe before next flower session and you will get fatter buds on top
And have you heard about the twisting of the main stem and breaking the inner node or bone / pipeline during veg cycle
You can do this a couple times and it will heal itself but the main stem will rebuild and get fatter thus producing fatter buds
Do some research on it, it will make a difference
I would do a tutorial on it but have not specimans to work with
That is all I have foor now and I am out