Speaker cable and brightness control

I'm not new to the Hi Fi world but have gradually developed a hearing issue over the last 10 years that makes me very sensitive to bright, medium to high volume sounds. I have used electrostats for the last 25+ years and it was explained in another forum how the diminishing impedance attendant with increasing frequency can accentuate the perceived "shrillness". This suggestion makes sense to me. So you have some idea of my starting point, my present system consists of the following: Shanling S100 solid state CD player, California Audio Lab tube based DAC, Rogue Audio Sphinx hybrid amp and bi-wired Martin Logan Odyssey speakers.

It was also pointed out that an amplifier with a tube based output stage could improve my situation and I believe that would probably help but, for the same reason that I'm sticking with my ML's, I really can't afford the expense.

This leads me to my question regarding speaker conductors. The varying opinions and arguments on this subject are wide and often contradictory with some saying that there is no difference between the various options, to one self proclaimed audiophile commenting that if you can't hear the difference, you should get out of the hobby. On one hand, I suspect that some differences are measurable but to say that they are so obvious that one should abandon the hobby if one is unable to tell the difference is absurd. In a previous post I pointed out that I seem to be one of those unable to detect differences after comparing a pair of borrowed $5000 cables to my own which would be considered adequate by most standards.

Disregarding these arguments, I would like to know if there are some general guidelines for objective and measurable qualities of speaker cables such as construction material, solid or wound, length, etc. that would give one a starting point in an attempt address individual listening tastes. In my case the goal would be toward reducing brilliance while maintaining detail. I suppose this would interpret to a warmer presentation which some refer to as vacuum tube sound. Any suggestions would be appreciated.