Hi Chris,
Would this work for you?
Scene file:
https://www.amazon.com/clouddrive/share/BY4yHDSU3zuLedz16AQxieFRA8JWpIoOJ9AO8KiF9RB
As a side effect: If you place the MG-Cloner now in a MG-Tracer, while it is in Connect Object/No Vertices mode, you can get a Spline that has the points where the Spheres should sit.
If you want to use the Tracer Spline, the Sphere will sit on the Vertices.
To get the Tracer Spline working in the same way as the Spline.object that you had in your Plain Effector, just drag it into the Falloff. Then select the Spline.Interface and save the curve, then select the Tracer Spline and load the curve into this (Falloff>Tracer> Layer> Spline interface).
Workflow screen capture, have a look here:
https://www.amazon.com/clouddrive/share/k4kwM2tcp3dPmk9AMo20JHPhnHr2qBRkmhF1d9Dl0RV
All the best