It is a better idea to prune your vine every winter. I have only a few but they are Guyot pruned every year in early January. Now if you want you can cordon them and leave say six or seven spurs per cordon. Then every year prune the spurs back to two buds, again do this in early January. In the summer the extra growth must be heavily pruned back you want grapes not vegetation . So all the main shoots have to be stopped when they are at the top of the wires and then all the side shoots, I let them have one leaf, have to be cut out regularly. In this way you will have a neat vine and also it should be productive. The vine in the center picture is a single Guyot and the one in the end picture is a single cordon or spur pruned vine, the first picture shows what your vines should look like they should really be kept to about that size. Good luck!