Deck Gate design for offset posts
I believe that you are over thinking the need to have the gate be somehow &quot;even&quot;. You should just hinge the gate at the post that is on the side nearest the street. Then just simply arrange the gate to swing up against the deck side of the closer post. The diagram below shows how it is done. The typical hinge usage for this type of application is also shown.

As you can see from the above diagram the gate ends up being &quot;even&quot; (parallel) with the deck boards.