AFA defol, look up schwazzing if you want to see how extreme you can go. I usually just follow a method of removing all fan leaves and any other leaf that is blocking light from getting to bud sites. I've tried the "21 days after flip" method and it does work but I get nervous about mold and mildew having the canopy get that thick.
I scrog so my rule of thumb is getting the canopy to a point where I get good airflow through the canopy so leaf removal depends on that more than anything else.
As far as your yellowing issue, under LED, almost always it's mag deficiencies. If it's nitrogen deficient then you have a lockout happening somewhere. I'd check pH both soil and feed solution.
I scrog so my rule of thumb is getting the canopy to a point where I get good airflow through the canopy so leaf removal depends on that more than anything else.
As far as your yellowing issue, under LED, almost always it's mag deficiencies. If it's nitrogen deficient then you have a lockout happening somewhere. I'd check pH both soil and feed solution.