I'm doing the same as goose however I used heat shrink 1/4" long every 8" to hold the twists in place. I do think that a sheathing would definitely improve the looks of the speaker cables. Check out grannyring (s) posts for the materials he uses.
Duelund 12AWG speaker wire sheathing
I bought four 2 meter runs of Duelund Wire 12awg (DCA12GA)Tin Plated Hook-up Wire. I am using bare wire connections for the amp and speakers. I would like any recommendations on sheathing material/tubing to run them parallel so it looks cleaner. Any reason not to have them touching? Any recommendations on material to use? I would also look any impressions of those who have used Duelund 12AWG.