I had to splce 2 3/4″ 4x’8′ sheets of ACX plywood to make each wall panel. CDX could be used and is cheaper but it contains many more voids and imperfections which could compromise the wall.
I used a half-lap joint 3.5 inches across to join the two sheets. I use a straight edge and a router to remove half the material on the lap joint.
The sections were joined with Titebond III and as much pressure as I could apply. There is a saw horse located directly beneath the joint supporting the load on top.