Crimping the two hot wire tails together across the inside of a corner is simple and saves a lot of hardware and time and connections. It let's you focus on using the bullet nose ceramic insulators for a good solid tension connection. 

I use 5 HT wires with only the middle one hot for my Herefords including calves. I ground the rest.  In the north you are going to have snow build up. You could energize the middle and top wire and ground the rest.  I would never energize the bottom wire as weeds will suck a lot of your energizer's joules.

Jim