Silver, as Cal says 2 high tensile wires on regular wood posts with an insulator (watch the quality of these - some are utter crap and break the first time wildlife hits the wire) If you have a 6 foot long, 4 inch round post at the ends and corners a 3 inch post is plenty heavy enough in between. Remember an electric fence is a mental barrier not a physical one like a 4 strand barb. No need for props - just sink the posts in deep enough though because you don't need the top wire as high as you do with your top barb wire. If your end posts pull out or angle you are tightening the wire too much! It depends on the terrain but you can put the posts further apart than Cal suggests on good flat country. The posts are only there to hold the wire upright and off the ground, cows wont be rubbing on them or rubbing the wire grazing through the fence like a barb one. See the beauty of an electric fence ? not only does the shock keep animals in, it protects your fence from getting damaged by them

But get an adequate charger and keep it going - I would suggest a fairly inexpensive solar charger would be the way to go on a small run like this.
In the past when we got oil wells or pipeline leases on our place I offered to electric fence around the lease sites for them if they provided me with a solar charger. That was a real good deal as they even paid me for my labor - I don't think they realise how cheap it is to run a single strand fence around a lease site!