Looking fantastic Hexa, rapid growth on the big one! I wouldn't say light stress no, all the water that goes into the plant must come out of the plant, it is a cycle, In plants, water movement from roots to leaves, driven by transpiration (water evaporation), relies on the cohesion-tension theory, where water molecules stick together (cohesion) and are pulled upwards through the xylem, creating a "tension" or negative pressure, when a leaf starts to wrinkle ever so slightly like its been in the bath too long, its just a indication the leaf has a little more water stored in it than is normal for whatever reason, maybe RH% peaked high for a few hours.
IF you added 10F and dropped 10-15RH%, she would start to erect everything rigidly and look like she was praying. More transpirtation = more suction force = more water movement = more nutrient uptake = more stress.
If you dropped 10F and added 10%RH% she would droop barely grow as photosynthesis would barely happen, meaning no suction is created through water cohesion.
Slighlty downward tips say to me, turn up the transpiration 1-3% (increase water usage through stomata) to increase pressure.
But honestly, your plants are looking great. Maybe bump the temperature up a degree or two to encourage a slight boost to transpiration if tip slanting down bothers you. There is no right or wrong; all that matters is you grow! Keep doing what your doing, look forward to seeing this genetic flower.