are you sure we can draw so many conclusions from your test charts
you use "bicubicresize" in your original script, so is it -0.6/-0.75/-1 ?
is it also a bad idea to upgrade LSF with spline36 ?
anyway, I guess you agree that the same grainsize for bright and dark areas is a problem ? you don't wanna have huge grains in open skies for instance
and what is "grain_texture" supposed to do ?