I did a trellis system but got tired of having to crawl under them to wrap mesh bags over the fruit and also to harvest. I did not think of using 4×4 posts but they could have been high enough to walk under.
What I did was mostly a tweak on the Heading of Grapes I found was done out in the Grape Fields in California. They did the heading only to get more varieties and of course took a hit on quantity of grapes per plant.
Thanks for the discussion.