I've been working all weekend on finishing up the back gate. The boards are all cut and I mounted each gate for a dry fit to see how they hold up.
They look good, but I am very concerned about the weight. These are not mortise and tenon construction (too expensive for custom built, and I lack the skill for DIY). So, I reconsidered the design and switched the top support rails on each door so that the horizontal support runs from the top to each hinge - it looks more like two letter "Zs" stacked on top of each other instead of the pattern shown in the image above.
This should re-direct more of the weight (and potential sag) to the hinges. In addition, I am going to install a metal cable on each door to help prevent sag. These won't align with the horizontal supports, and they will look unattractive, but given the heavy weight of the doors, its a necessary preventative step to postpone sag.
On the other hand the front face of the doors look nice and will provide privacy to the garden, especially since its on the far side of the garage and out of sight from the house.
When open, it will at least give a hint to the outside world of the paradise on the inside of the gate.
Next step is to remove the front facing boards and begin the process of staining the gate frame green and the face boards cedar. It will take a couple of days to complete two coats.