Novice seeks advice on refreshing old vines

[dagnew]

We planted two Concord grape vines about 8 years ago, at our home on Cape Cod, Massachusetts. They grew up two pairs of posts to crosstrees and several lateral sticks approximately 7 feet off the ground. We pruned them most years, but I'm not at all sure that we did a decent job. They produced what seemed to us like quite a bit of grapes, but the grapes seemed fairly small and we didn't protect them from the birds, which ate most of them.

Recently a strong winter storm blew the whole thing down. The vines are now rather long, tangled, and difficult to 'put in order'. Please see photos below. Lilacs and forsythia are just budding, if that's helpful information.

This seems like an opportunity to 'start over' and get it right with well established plants while pruning and training them properly this time. I'd like to do whatever might result in healthy productive grapes, but would prefer to have the vines much lower than they were for ease of tending them. I'm basically wondering how severely I can prune them without harming them.

[JONA]

Hi Dagnew,

Look at the point where the trunk of your vine devides into separate branches. Follow those individual branches and each time you come to a side shoot cut it back to two buds.
Once all the branches are done you can decide whether you have too many.
I suggest you put in a couple posts either side of your vine.
Run a couple of wires between them one at three ft or so and one at four and a half or so.
Tie one branch to each wire and train along.
When the side branches start to grow and produce fruit trim back each shoot to two leaves beyond the bunch.
That should keep the vines tidy and easy to care for.

[dagnew]

Thank you, John!
Do I need to do this as soon as possible given that Spring is beginning to spring?

[JONA]

As soon as you can dagnew.