SWL: We understand that Correlated Color Temperature (CCT, Kelvins) does not adequately describe the ‘non-visual’ response to light which is better described by melanopic lux (Lucas et al., 2014 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4699304/) or the melanopic / photopic lux ratio (see https://fluxometer.com/rainbow/ for examples). We did not have time in the talk to review this issue, unfortunately.
SPD is of course better, but Kelvin is often used. 3000 Kelvin is generally indicated as upper limit for colour temperature; but of course lower is better. It’s all about avoidance of blue light for species active at night.