My reversing bulbs arrived (with quite a thud) through the letterbox this morning. Whoppers aren't they, Mike!
I note though that you recommend the red brake/fog bulbs for clear lenses. I'd recommend them for red too, as the red light will all get through the lens. The white one will be emitting blue and green light for nothing, as the lens will absorb it all. In other words I'd expect the red ones to be brighter than the whites when fitted behind a red lens.