We grow 3 rows of grapes and I have left the pruning to my father in law until the past several years. now he is 90 and has dementia but he still wants to do it. its a disaster but I figure it isn't gong to impact the rest of my life once he is gone. I let him fiddle out there but he doesn't cut off nearly enough usually. So, we go behind later and finish it up. We have concords and a few seedless and we treat them all the same way. we try to leave 4-6 buds on 4 limbs on the grape vine. it looks HORRIBLE when we are done BUT it works. otherwise there is too much plant to support and the grapes aren't nearly as nice. You will be removing 85-90% of the vines when you prune. we might prune to severely for some people but it works for us. here is a clear guid from Ohio state U Extension office.
https://ohioline.osu.edu/factsheet/HYG-1428