Speaker cable length

I would make them the same length.

The only thing to be aware of is it's gonna cost ya.

Most people probably can’t hear the difference between two different lengths or is their system capable to reveal the difference. How long of a set are you needing? If it’s a fairly long stretch and you have to watch the budget I’d suggest Canare 4s11. It’s very affordable and extremely flexible. Used in pro audio and live settings so the geometry is designed for longer runs to not pick up noise. It’s a very good and a great cable to start with as it might be the end of your journey. Can be purchased online and even Amazon. Does take a lot of hours to burn or settle in so do not rush to judgment.

The biggest issue with mismatched cables is resale as you swap them out, cuz in this game you will, just part of it. Resale is not going to happen unless someone has your specific configuration. If you do inexpensive, or DIY doesn’t matter.

I just swapped out my Benchmark speaker cable with SpeakOn termination for some Audience FrontRow also with SpeakON terminations (you can get any termination). I only need 1 meter lengths because I have monoblocks right beside each speaker. I use 15 or 25 foot of Benchmark XLR cables to connect my amps to my preamp. This way my rack is sitting beside me and nothing is in-between my speakers.

Comparing my FrontRow and Benchmark cables are an apples-2-apples comparison. One cost $200 and the other cost $3600.  The Audience is a bit better but I was very happy with the Benchmark prior to the FrontRow. I only bought the FrontRow because I had saved so much on my other gear that I had some extra cash in the stereo budget to splurge.

If you are going to use very long speaker cables I suggest you use some pro cables like the Benchmark so that you do not get killed by the cost. They are excellent.