i am using a mini halogen lamp, and a HO tube. is there an optimal substrate? ive seen so many things online i don’t know which to believe.Sounds nice! But what type of UVA/UVB lamp do you use? Maybe you have a photo of the packaging?
To keep humidity high, try not to use a fogger or spray substrate surface, but pour some water in the corners. This makes lower layer damp and top layer dry and helps to keep humidity high for longer periods.
If you use coconut fiber (not coir) it could give off some color when wet, maybe that's the reason for overall darker colors of your guy. Just in case, coconut fiber is not the best option as a substrate (because of fibers, actually).