This group is great! I've only made lumen prints using natural UV light. Apparently your light box shortens the exposures compared to that. I too found that wetting the paper gave more interesting results. Also, old paper seems to give more color. I don't know if it's just because it's old, or if the coatings were different then. Last Summer I bought two 100 sheet boxes of Unicolor Gallerie. Probably from the 1970's. It yields interesting reds and browns.
Keep showing us your results.