I've never found it necessary to cover red windows for ISO 400, either color or B&W, whether with Kodak films or Lucky SHD 400, or even the very inexpensive J&C Pro 100 -- even in a camera with the red plastic gone from the windows. I've seen examples of fog-through with Efke 100, however, and I can't speak for Delta 3200 (though TMY pushed to 3200 showed no problem, it wasn't exposed to sunlight while in the camera). The only problem I've ever had that I could reasonably ascribe to the red window was edge fogging from reflections, which will happen while advancing (when the red window has to be open) just as readily as when the camera is sitting.