Hey, in my many years of growing, i never found a good way to battle thrips, nothing seems to really kill the, but on the other hand, part from the marks they leave on the leaves, and the fact that i hate seeing them, they don't seem to cause that much damage. whenever i had an infestation ( mites or aphids) i did the 3 time spray cycle, that is i sprayed every 3 days, 3 times, and that seem to help, especially when using azatrol or azamax, rather than neem oil. Never sprayed daily, as always recommended to spray hydrated plants, and growing in Coir based, its good to let the top inch get bone dry. If your plants are rootbound, transplant them - stressed plants are much more attractive to pests, and are less capable of defending themselves.
I dont like soil, prefer a more soil less medium, with feed or added organic matter. Also, prefer guano & worm castings to manures. not sure what soil you got and what/ why you want to add amendments to it, also what amendments?
i think that the plant in the pics looks good. the leaf claw (where the tip of the leaf curls down) is a sign of overferlizing, so go eas