I use the last product on your Kencove list (which appears to be the same as the one just above it, which is just white instead of black).

I do know insulation is key, as regular UF wire (120/240 volts) will give you problems since electric fence voltage can be many times higher.

I run my underground fence wires (where I think I need extra protection) in the cheapest (irrigation) poly pipe I can find.

Have you asked Kencove "why so many choices?"?