Hey Dan! Thanks so much again for your help.

In the end the expression I used is this:

var L = index > 1 ? thisComp.layer(index - 1) : null;
var C = thisComp.layer("Start");
var ctrl = thisComp.layer("CTRL");
var p = L ? L.position : [0, 0];
// Controls
var d = ctrl ? ctrl.effect("WaveLovers")("Delay") : 0;
var g = ctrl ?…

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