Q.How to trim the grape vine during the growing season?
Have two vines on a chain-link fence and trimmed it back in the NC winter but it has put out lots of little clusters of grapes and I don’t want to have too many that steal the energy from the vine and produce poor grapes.

Pruning while the grapevine is dormant is most often done but summer pruning has it's benefits.
Here is a few links with more information.
http://aces.nmsu.edu/ces/yard/2005/072305.html
https://www.gardeningknowhow.com/edible/fruits/grapes/prune-grape-vine.htm