This will all basically come down to preferences . Personally I like to only defoliate were I have too in order to make more light penetrate on the cola's . If you need to defoliate heavily , I suggest doing it every couple days until you hit the desired canopy that you like . This way you can take some watch how you plant reacts to it and then repeat if needed . I say this so you can prevent over stressing your plant . As for the nutrients you have selected for your grow they are all high quality nutrients so you should be good on that aspect , if they are used properly they will surely boost growth and yield in your plant(s) . Over all looking at your plants I would say they have been defoliated enough , now would be the time to apply some lst in order to get the tops in maximum lighting to achieve maximum yield . They look like they are well on to providing you with great medicine . I hope the information provided helps you understand the defoliation technique abit better as well as some of the benefits it brings . - Happy Growing !