Snakeeyes, same here, moved a lot since 2012. So I did just like you, kept the loop of 15ft for L/R mains and for center 10ft. Now I’m no expert or engineer I did read a post by “Gene” that he uses 10 gauge AWG wire for his high end speakers. So just for the hell of it I went a got 90ft of 10 gauge AWG speaker wire, with locking Banana plugs and Y boots to go over the ends of the wire, came out real nice plus the cool looking factor of the wires. I do have a XPA- 5 200 X 5 @ 8Ohms. Inside your speakers be it bookshelf or towers from the crossover to each speaker the wires look like about 14 gauge. Does it matter? on long runs 50ft or more is what the experts say. With this hobby for me anyways I have always been a tweeker of trying to get the most out of what I have. Sometimes it’s better sometimes a waste of money.
Mike