Thank you all. You've helped me towards illuminating a SciFi scene with a $$ Vanishing Point 'Maintenance Tube' set that has 'light panels'. Upside, now they sorta work, iteration required. Downside, I was a _tad _exasperated before any test-render looked hopeful-- And ONLY in Superfly !!

Also, you gave me the incentive to poke about in Materials' 'Advanced' parameters...

PP_11.3 Care: If you dial any parameter up to 'silly' in 'Advanced', save scene before you render, okay ?

"First, I couldn't find the light switch. Now, I'm getting a tan !!"