Our pens and alley ways have 2 7/8 post cemented in. 2 3/8 inch pipe saddled on top of the 2 7/8. 2 3/8 inch on top is plenty strong, cheaper than 2 7/8, less cutting and welding for the saddle and looks better IMO. I have 5 rods 3/4 for the fence and a single rod between the post welded...