I'd play with all the TR settings and see which one you like best for the conditions. I basically don't pay attention to the names and just think of them as options 1-5.
WRT to throttle response I think they each do something slightly different. For example, for any offroad where I'm using low range I prefer rock crawl mode, regardless of terrain, because the throttle response is less sensitive.
Of course each TR mode does different things with DSC too, so see if one is more forgiving in mud without needing to turn DSC off completely. I have no idea if this is true, but a dealer rep at an offroad event told me in Sand mode TR all but turns off DSC anyway, without you needing to. Of course, if you read the manual they explicity tell you to turn off DSC in a few of the modes if you feel the need, so the dealer rep may not be right.