can you help me narrow my speaker cables short list please?

Put down the snake oil and get the cheapest copper wire you can find. Just be sure the gauge is large enough for really long runs. You could use a coat hanger and not tell the difference, and that's a fact.

I bought these and they are easily worth the asking price: Good wires

Twisted pair of magnet wire. After all that’s what you have > 50 ft of in the speakers.

@square80

its only a fact for those with cheap gear and/or genetically deficient hearing. 

15 foot is a long distance is there anyway you can get the amplifier closer and have longer XLR cables? 
 

if not, you’re not going to really get better cables than what you have now in your budget. what kind of speakers do you have? What kind of electronics do you have?