I am using an actual slide for the fifth guitar. I kept it as low as possible to get the weird effect. I used the “Jazz” effect on the Line 6, where I usually just use the “Bypass” for the acoustic. I also turned down the treble as much as I could, and lifted the presence up.
Ok, the part below, the C6 chord, MUST be a piano chord. I couldn’t figure out how to finger this myself, even using my thumb. What I would do is just leave the third fret on the A string open. I did it in the recording as well.