LST only or can I defoliate it!!

There are only 2 reasons to use defoliation. The first reason is when leaves are stacked on eachother blocking the airflow and moist can not escape from the bottom of the leaves causing mold or fungal. The second reason is when large leaves on top block a huge amount of light for a larger part of the plant. Your plant is really bushy so you can do some defoliation but please don't overdo it and keep the 2 reasons above in mind while doing it. Other than those 2 reasons you just damage the plant and it will decrease yield. Training techniques like LST or HST are only there to give budsites more or the equal amount of light from your lamp. So while doing these kind of techniques look at your plant from above and see if you can create space for light reaching lower budsites. Make sure that you do not create gaps in between because than you lose light and again decrease yield.