For wire, find and buy top quality “fanatically shielded” specialty 10 ga used for the most sensitive commercial applications; super critical robotics for example.
For ground information go to the Equitech website. The man behind Equitech’s patents, Martin Glasband, has created products that have solved more ac power noise problems than “all” the other electrical engineers on earth! Mr Glasband is a real expert; has authored sections of the US Electrical Code. He has helped many personally.
Also, the most important factors in your new wire are
1. Shielding
2. Termination
3. Placement in your walls.
4. I would use at least 3 separate runs which gives you great flexibility for experimentation in the future.
With quality cable don’t give a thought for a few feet here or there. Irrelevant. However, make sure you have enough that in each run the wire is relaxed; do not install it ‘tight’.
Be aware that there’s an endless amount of “voodoo” and utter “nonsense” from some “fools” in this forum. They are not well meaning; just plain ignorant, stupid, or both.
Also, if/when it’s affordable an Equitech 2Q or 3Q will improve your sound “ dramatically”. Best wishes. Pete