Grapes love to be prunes and try to overcome our shortcomings in pruning knowhow. I count about 80 buds on that vine- so you should be pretty good. If you want to cane prune, leave a few renewal shoots growing during the growing season to form next years canes. Prune out the heavy wood each year above the main trunk and replace with those renewal canes. If you want 4 canes, leave four- two each direction from the two wires. If you only have the top wire, leave two long canes for the shoots to grow out of. If it isn't raining too hard this weekend for pictures I will try to get some when I go to Willsboro to begin pruning at the grape trial. If it rains too much I on Friday, I will try to go to the other demonstration locally. If that doesn't work out either I will take some pictures as I am able to cane prune my 4 arm vines.
I like the VSP for pruning ease. Just establish cordons on the fruiting wire and train the growth vertically between catch wires. Then the next year prune to leave 2 to 4 buds on most varieties just above the cordon. It is quick and easy and leaves the fruit with better exposure.