From my personal experience (very similar to yours), I found the main issue for my plants drooping was the light intensity and period of being on. Whilst you can keep your lights on 24hrs per day, some strains struggle to keep up with the photosynthesis and droop its leaves to lower the intensity hitting the leaves. I've found once I reduced my lights on period to 16-18hrs/day and extended the distance - the leaves propped up and looked much healthier. This is ofcourse assuming your VPD and other environmental conditions are acceptable (which sounds like it in your case).