One thing you might consider is rather than using cable risers, suspend your speaker cables with string from the ceiling. The advantage here is your speaker cables can be completely isolated from the power cords and other connectors because after leaving the amplifier terminals they go up, not down into the cord milieu.
The improvement many folks assume comes from the risers actually comes from getting the speaker cables away from the power cords and other connectors by lifting them off the ground. However, with risers you are still in relatively close proximity to the other cords in your system.
This tweak costs you nothing.