ps: my English is poor
if you use
fInteriorShadowDistance=0.0000 = you get no light in same light source
fInteriorShadowDistance=256/512 = you get circle of light around player like
but 0 remove all ugly shadow on player and stripped shadow
if you have SBT shadow will look very ugly and pixel even with 8k only 16 k or 32 k fix it
but using fFirstSliceDistance=0 even in 2 k shadow in better , you get some flashing effect , but it get ride of pixeling shadow effectt
and some one test this values