Check this out.
Using thin wire with a low power amp vs high power amp. Your 8 ohm speakers are 50ft away so you connect them with 100 ft of 29ga wire. That wire has 8 ohms, just like your speakers, so half of your power is lost in the wires, and half dissipated in your speakers. So your 10W amp supplies 5W to your speaker, and it's not very loud. Now change amp to 100W - you'll get 50W to your speakers and they will still be quite loud [assume the wires aka speaker cables don't melt...].- so arguably, large cables are more important to a small amplifier where there's no power to waste [other than the melting / heating issue, which in any real case won't be an issue.]
If you compare 100ft of 12ga wire vs 16ga, the resistance increases from 0.16ohms to 0.40ohms. I also doubt you'll hear any difference.
Although you may have some effect on the damping factor, and in fact get less bass control of your speakers ....