Hi Bsr045,
I see a lot of stacked shadow area below the upper canopy, If I may suggest, I'd say selectively trimming maybe 10-15 leaves could offer a benefit to the plants, as they would be better able to utilize the the light that they are receiving from above, it's not really a good thing for only the top 20-30% of the plant to be absorbing most of the light, it's more ideal to try allow for the light to be able to cascade downwards and disperse evenly throughout the plant.
Also I've even noticed potency increases by selectively trimming plants and by super cropping, if you just let the plants grow however they want and don't interact with them at all, then they have no reason to defend themselves and will not put out as many hormones and chemicals into the buds and leaves in attempts to fend off herbaceous predators from eating the leaves and the plant itself, so if you are able to just lightly trigger this response within the plant gradually over 2-3 periods of light to medium defoliation & LST (LST during veg mostly, not flower unless for height issues etc), you can typically see and notice a boost in terpenes and other cannabinoids.
The buds of the plant is where mostly all of the thc and other active cannabinoids are released from, if no light reaches into a majority of the bud sites, then this also gives the plant no reason to defend itself from the light and UV that they are receiving, the bud sites need to recieve a decent amount of light in order to trigger this response, which is why defoliation works, the leaves are only part of the equation, a light defoliation is what I recommend to anyone whom is already several weeks into flower, if you go too heavy at it, it can add weeks to the final flowing time, so just use caution and just clear what you feel is necessary, and whatever you think/feel will allow and improve air/light flow through the plant, especially down the center.
Plants aren't designed to grow perfectly 100% of the time, they put on leaves (and new growth) to over compensate and better there chances to absorb light and complete photosynthesis, each plant puts out more excess leaves than it actually needs to survive for each individual plants own survival, many times it can be up to human interaction to balance out a plant to help it reach its ideal structure.
Also be aware plants have back up leaves that grow in to replace others that are lost or extracted in the wild; by natural growth detriments such as bugs,caterpillars,hail, herbivores, wind, drought, etc. Plants defend themselves by responding to this with replacement leaves just like a shark or crocodile with its spare teeth continuously being replaced, but only to a certain point, it's best to only remove a certain number of select leaves so that the plant is allowed to replenish itself without experiencing too much shock or disruption in its growth.
It's best to wait at least a week or 2 between trimmings so that the plant has time to heal in between, so it's best to get as much clear as you (and your plants) feel comfortable with each time, as it's better for the plant to not be in constant recovery mode.
Happy trimmings, and be sure and save the leaves for fresh Cannabis tea or fresh salad greens if you are able, lots of good healing left in those leaves.