Re: fence gate in a gate
Build your man gate any size you want. Fill the rest of the space with the larger gate. On the operable end of the larger gate, install a gate drop rod like this:
The man gate will get the normal latch, the catch will mount on the larger gate.
You don't have to use a metal framework like what is pictured, you can wood frame it easily enough. I would recommend that a caster wheel be installed on the larger gate to carry the weight because a post alone will have a tough time of it. Also, when you install the drop rod, it would be a good idea to pour a concrete footing 6" to 8" square for it to drop into. This will keep the gate stable and well supported.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!