The best advice I've seen so far is to just cull every cane/branch outside the main stem except vines running on the structure. It would be a year without fruit, but it puts me into a great position for the future.
Not sure if I should just eyeball dead vs live canes during the winter or just cull them all
These look like a Concord offshoot breed so that is good advice. I can't start trimming for 2 weeks, so by that time it mah be difficult to determine, what to trim.
I could video call you and you say 'cut' or 'no cut'
so by that time it mah be difficult to determine, what to trim.
Nah. The older they are, the thicker they are. It will be obvious what's what. Prioritize the thicker, older branches but otherwise you can trim back pretty indiscriminately.
You trim them in the fall (like now). They will grow like a motherfucker in spring, but if you cut a ton now it will affect your yield next year. It will take a year or two to recover, new vines don't grow a ton of grapes. Maintain the vine as it grows, keep the new curlies where you want them to grow. If you neglect it, it will get unruly.
Note that if they run into the ground, they will root. So you can use this tactic to grow new vines. They're very hardy plants and will survive pretty much everything. Like tomatoes, rain will affect the quality of the grape. If it's too much rain, they'll get bursty but if there's too little they will be smaller and dry.
Source: I grew up with a huge concord grape vine in the back yard.