I'm a newbie, but I'll have a go at this.
Looks like you have some vines that are growing on some form of Geneva double Curtain. I see a few rows with cordons that are low and canes that grow upwards (looking like some kind of VSP) and ones with cordons that are high.
If I had to guess since you're in Northern Illinois and they're wine grapes you're looking at Hybrids. I'm going to guess Marechal Foch, just because it's my understanding that it was pretty widely planted. If it is a white concord looking grape, its probably Niagara.
If it were me I would go with spur pruning. Blue is your trunk and cordons, and black is your 1 year canes coming off of your existing spurs. You're going to prune those back to 1-2 buds depending on how many buds you want on the plant total. Typically the number of buds on the plant is a function of pruning weight. The more you're taking off, the more buds you will leave on the plant total.
Blue is your cordon, Black is your 1 year old canes.
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Other forum folks can correct me if I'm wrong here (free advice on the internet, you get what you pay for.) These look like well taken care of vines, so you're fine leaving a good number of buds on the plant.
When you're done, if viewed from the side it should look like a T. Assuming this is some variant of GDC:
1 year old canes that are growing low from the trunks or cordons should be removed entirely. Don't be timid. When you're done it's going to look like you gave these vines a buzz cut rather than a trip with an inch or two off the top.
This past winter was pretty rough for us. There is a good chance that you've got a bit of cold damage. If things don't leaf out the way you expect after your pruning, don't think that you harmed the plants. It's most likely they were already damaged from the winter. You can check the buds by nipping one off on an area you plan to prune with a fingernail or something. if it's still green and firm, then it's fine. As your pruning I'm sure you'll find some bits that are dead as well.
I'm sure there is plenty I'm missing on this, but this can help get you started.