This has been discussed ad nauseam on here. Al (almarg) has by far the best comments available. Maybe do a search. (I did the search for you below.)
I can tell you that you should NEVER coil the wire. It will cause inductance. You should, if you have to, use a loose figure eight type configuration.
https://forum.audiogon.com/discussions/compensating-for-different-speaker-cable-lengths?highlight=di...
https://forum.audiogon.com/discussions/are-unequal-length-speaker-cables-really-bad/by_member?userna...
I can tell you that you should NEVER coil the wire. It will cause inductance. You should, if you have to, use a loose figure eight type configuration.
https://forum.audiogon.com/discussions/compensating-for-different-speaker-cable-lengths?highlight=di...
https://forum.audiogon.com/discussions/are-unequal-length-speaker-cables-really-bad/by_member?userna...