The grape trellis for commercial wine production is a single wire on eight foot posts about ten feet apart. With added end bracing. the vine gets pruned into a "T" shape with up to five buds on each top arm.
A Kniffen trellis looks like a "T" over "T" for table grapes with two wires And up to five buds on each arm.
Your gonna prune after solstice. and if its been a few years your going to chop a lot out.
If you prune back too far the first year (and you may have to) it is possible to not have many budding points on the new arms (and a smaller crop of grapes as a result). This too will pass on subsequent years.