I took down two barns and used the metal roofing to build one barn. The metal had existing holes when previously installed. These holes did not line up with my new framing. I just used silicone caulk on the holes. The way I found the holes was to have my wife inside the barn, she would locate...
Agreed, I would remove the wood post and replace with a steel post. The steel post can be painted to match the fence. If possible I would support the end of the gate with a wheel. This will transmit the weight of the gate to ground.