I use the solo cup hempies to grow roots Jones.
You already have them established. Lol! Get those clones into something bigger than a 20 oz cup. Your T8s shouldn't be causing any problems. I can get right down on top of my plants with a T8 and they won't bother the leaves unless you're near the ballast. They're too cool to burn. But you may be too close for the limited number of leaves to root.
Are you adding CalMag to the water? With soil you have additional buffers perlite doesn't offer and CalMag additions are standard practice.
The yellowing of clones, IMO, is most often due to asking the plant to process more light than the roots can handle. Other than that you're typically looking at a nutrient imbalance.
I need to encourage you to start using my produce bag method and stop butchering the leaves of your clones. This may be one reason mine thrive. The leaves are always intact.
Also, next clone attempt make the stems shorter. You have so many nodes on that stem it's gonna challenge you to control vertical growth. How do you keep them under control once they start producing more growth? Most of us try to keep the structure low and controlled.