Our fence consists of galvanized posts cemented in the ground. Holes were drill through the posts and bolts were inserted to hold the wood rails. Then they filled inside the posts with concrete. As it sits the fence is 4.5’ high. We’re looking to make it 6’. The two options we have are leaving the two 2x6 rails and just installing new 6’ boards however the board will extend 2.5’ past the wood rail. The only other option i can think of is to chisel out a few inches of concrete inside the post and place a hollow 2’ piece of galvanized post on top, drill another hole through for a third rail and drop a piece of rebar in and fill it with concrete. The posts are rock solid but i feel like a board going 2.5’ past the rail is too much?