from all i understand, the value for light fading is *times the radius of the light, right?
so, where's the difference, if any, between a light with 256 radius and 1.0 fading
and one with 128 radius and 2.0 fading...?
(i sure can tell i makes no difference concerning texture flickering so far )

Light fade is controlled by other things. The 'fade' setting on a light is actually it's brightness, and has nothing to do with radius. Thus, the difference between a 256 light with 1 fade and a 128 light with 2 fade, is that the latter will light up an area that is half the diameter, but it will do so twice as brightly.

Light fade is controlled in the lighting settings, and some game settings I believe.

I always thought that radius setting was what a light defaulted to when you placed it somewhere (before scaling it up or down).............anyway

As far as your flickering is concerned, you have too many lights acting upon certain models. Run the # of lights debug. Red area's are bad. Lighting can be a frustrating thing because often surfaces/models will be affected by lights far beyond their supposed radius. I'm not entirely sure why this is but it seems to invariably mean having less lights. (To be honest I have heard that doing a search and replace/switching the light objects can alleviate this issue, but I cannot substantiate this)

*EDIT: Partial ninja