Advice on Speaker Wiring - Larger Advent w. McIntosh MA6500 Amplifier / Speaker Settings

I recently connected a second set of Larger Advent speakers to my McIntosh MA6500 Amplifier.  They are in another room, about 70 feet away.

I used 16 gauge Rocketfish speaker wire, that I ran down under the house in the crawl space. The speaker wire came in a 100ft roll, so I have about 30 ft left over.  

I'm wondering if I should cut the speaker wire, so that the wire is the shortest distance possible between the amp and the speaker? Or can I leave the full 100ft length with the excess spooled up behind the HiFi rack, in case I ever want to move the system in the same room? 

Will there be any audible difference in the sound between running the speaker wire 70 ft vs 100 ft?

Also, the Larger Advents have settings on the back to switch between Normal, Decrease and Extended. I have them set on Normal. Any information on what the difference is between these settings?

Thanks in advance!

Paul in Astoria