According to Albert Porter and other posters, even relatively thin speaker cable will pass higher amounts of current than most home amplifiers generate. But are there other ways in which using a thicker wire might affect the performance of an amp?
I was trying to inspire you to think beyond wire gauge.
I don't disagree larger gauge might be better, my favorite speaker wires are about 12 gauge under all that outer wrapping.
Thicker wire effecting the amp is perhaps the wrong way to look at it. The wire is passive and always lossy in relationship to the best ability of the amp. The best a wire can do is move most of the energy to the speaker with as little damage as possible and hopefully not picking up too much RF, vibration, inductance and other problems in between.
What I'm getting at is two identical wires (gauge wise) can sound totally different but not necessarily because it's effecting the performance of the amp. More likely it's showing the personality of delivering the energy to your speaker. Sure, things like capacitance and resistance are real and effect the sound but there are other things that are not so easy to measure.
When we have a perfect way to move that energy, there will be no need to discuss wire any longer.
Basically, choosing the lesser evil in wire is like choosing other compromises within ones system.