Disc brake cooling, anyone done any ducts, scoops or....?

I found in general racing (rallying) that running without shields was cooler than with them in any form. But the dust and dirt could be problematic, especially when it became muddy. I have bent the dust shield out to catch air but that was not as effective. If you really want cooling, ducts up from front are the way to go. It is kinda like a cool air package for the intake; the only consistently good spot is out in the clean air.

If you are drag racing, though, scoops might add a bit of wind drag....what is you actual use? Bonneville? Road race? Running moonshine?