We need to distribute correct information, when possible, many readers here.

I agree with MnRenovator radiator color makes no difference (unless its metalic).

Look up the emissivity (range 0 to 1) numbers for different paints, most run .80-.90 & are not dependent on visible color

from that reference:

https://en.wikipedia.org/wiki/Thermal_radiation

"Surface effects

Lighter colors and also whites and metallic substances absorb less illuminating light, and thus heat up less; but otherwise color makes small difference as regards heat transfer between an object at everyday temperatures and its surroundings, since the dominant emitted wavelengths are nowhere near the visible spectrum, but rather in the far infrared. Emissivities at those wavelengths have little to do with visual emissivities (visible colors); in the far infra-red, most objects have high emissivities. Thus, except in sunlight, the color of clothing makes little difference as regards warmth; likewise, paint color of houses makes little difference to warmth except when the painted part is sunlit.

The main exception to this is shiny metal surfaces, which have low emissivities both in the visible wavelengths and in the far infrared. Such surfaces can be used to reduce heat transfer in both directions; an example of this is the multi-layer insulation used to insulate spacecraft."

Why don't threads on this forum close after a certain amount of inactivity? I thought this thread was dead. I imagine Skyking made his decision as to building methods and materials long ago...

There are gaps in between the lines for a reason. Yes, suntuf panels admit light. Yes, shiny surfaces make better reflectors. Yes, a flat black steel roof panel absorbs more heat in sunlight than a white one. Whether or not a casual surfer will care if they are giving up 2% heat gain to have a tan roof, well I haven't one clue!