ohhh.... getting excited at that prospect Cath... pouring thru my own info archive too, along with insights from a few months back regarding how posers lights work (or don't work) based on reality. Adding a node to the light to correct the lights response to make it like reality. So I am looking forward to what you've discovered.  Between  my tests with your corrected probe, snapping a few raw exposures to build my on HDRIs, mapping out lighting grid for a tv shoot Tuesday night, and finishing a website for a deaf group I am involved in...I'd say I'm a busy dude LOL