What Kind of Grapes?
All I know, and I don't know much, is that your trellis needs to go with the grapes that grow in your climate. You don't want a bunched up canopy in GA because it's too steamy there in summer and you'll get fungus issues. So go for a really spread out airy type thing so you can spray every leaf easily.
I am big on zone jealousy! You guys grow stuff there that we can't! Best thing to do is go to local vineyards, and see what varieties grow well in your area, and order those. Look at those trellises, and copy them.
We did that here. There are commercial vineyards very close to us, growing table grapes. I was amazed at the miles of vineyards here with NO wine grapes! Not ONE!! But we copied their trellis and ordered hot weather craving wine grapes from places like Greece, Australia, etc. I didn't realize at first that the commercial vines who's trellis we copied are cane pruned, not spur pruned.
We started ours out with cordons, and are now switching to cane pruning because it just works best in the hot desert. It's tough to switch mid stream, so you are doing best getting it sorted out ahead of time.
Take a trip through the pruning and trellising videos over at you tube. There are many, and a picture is worth thousands of words for sure!!
Good luck with your vineyard!