Are these your current speaker cables? They have several desirable attributes such as the type of copper used, the gauge, and the dielectric material, i.e., 12AWG Long-Crystal Oxygen-Free Copper and PE dielectric. What do you expect to improve by switching to different speaker cables? I doubt you would reliably hear a difference (much less an improvement) between your current cables and any of the suggestions here. I suspect there are other areas of your system where the $1,500 could have a greater (at least audible) impact on the sound of your system.
Back in November, you were interested in tinned copper in cotton speaker cables. Were you ever able to try a pair of those?