Audioquest Robin Hood silver or Audioquest Thunderbird zero?

I am a dealer for AQ and I have tested a bunch of AQ cables and I have found their copper cables are very similar, just with an increasing gauge. They are pretty transparent/revealing with a noteworthy level of detail and have a distinct emphasis on bass.  I would not call them bright but they certainly are not warm.  This is across Robin Hood, William Tell and Thunderbird.  Not bad, just what I have experienced.  I have not tested the silver Robin Hoods and have no POV on them.  

I recently swapped in Clarus Crimson.  The manufacturer sent me a bunch of cables on demo.  I found them to be more neutral.  Treble and detail level was similar but the bass bloat I was experiencing in my system went away entirely but I wouldn't call them lean.  I was pleased enough that I am now a Clarus dealer and am planning to use the Crimsons at NY Audio Show.  

To be clear, not saying the Clarus is better, just more balanced in my system.  I am running an AVM Evolution A5.2 integrated into Vivid Kaya 45 speakers.  

the biggest difference is the amount of current these cables carry.  Their gauge increases and that is the biggest difference to me.  There are much bigger differences between Rocket 88 and Robin Hood than Robin Hood and thunderbird in terms of structure and quality of cable.