Instead of polietileno I used policarbonato 10mm strips that make exactly one turn less one diameter of wire
The wire is soldered on top of the strip o the right side and goes in the channel of policarbonato till where it will start cooling
Over the policarbonato I use some polyester tape to keep in place and than start the coils
The policarbonato has 0,5mm thickness so it will isolate well although should not be so much voltage across water
I don’t think it would ever go over 2kv
If so 1kv or less so the main idea is simply to prevent any arcs and short
It looks very nice