I think the mix of wood posts to steel t post depends on the terrain. The more up and down and curves the more wood.  My preference for most cattle fence is 5 T posts then a wood post all 10 ft apart with 5 wires top two and bottom two 12 ga barb and the center a 12 ga SMOOTH steel electric wire on insulators. I would strongly urge do NOT electrify a barb wire, for several reasons. jmho.

Jim at Dawn