Dear zieman: +++++ " I routinely change loading with different phono cables. The differences are not subtle. " +++++
as Audiofeil and Atmasphere posted almost always ( nothing is perfect ) the cable resistance value per meter is too low for take in count on cartridge loading and I agree with them.
IMHO what you are hearing is due to own differents cable colorations but certainly not mainly because its cable ( really low ) resistance. As a fact you, like everybody, don't want a high resistance cable where you can loose the signal high frequencies ( between other things ), normally a cable designer almost always works on a very low resistance cable.
Of course that maybe in one of those cables that you already try it its resistance could be really high but that is not the standard, as I told you: we are looking for a very low resistance cable as a rule.
Btw, the other subject that I always support is what Atmasphere posted: don't use the cartridge loading like a tone control/equalizer to compensate for " errors " somewhere in the audio chain.
Regards and enjoy the music.
Raul.