As for the weathering steel, USSteel put out several papers on it when it was introduced. They issued several warnings about the use of it that the utility industry has forgotten. Treated lumber should not be used in contact with weathering steel and it should not be used in areas where the water table may higher than the but of the pole. Poles should be sealed or adequately ventilated to ensure the patena forms completely on the inside as it does the outside. There does not seem to be a consensus on what constitutes adequate ventilation and it may depend on if you are in a very dry climate or a humid one. Poles should be protected from tall grass, weeds, or brush that may rub against the pole and damage the patena.