Have you considered a 16' long rolling gate that rolls along side your existing fence when opened. This is made of metal and you would attach your wood sections to it.
It may not be the most appealing at first but will probably still look the same in 5 years. Swinging 8' wood sections attached to 6x6 will not look as good in 5 years. I would guess that a bigger problem than the 6x6 deforming will be in the middle where they meet. The sections will twist.
It may not be the most appealing at first but will probably still look the same in 5 years. Swinging 8' wood sections attached to 6x6 will not look as good in 5 years. I would guess that a bigger problem than the 6x6 deforming will be in the middle where they meet. The sections will twist.