I'm interested in this too. I've already pruned a pile of shoots 3 feet high off just 2 of my vines. I chose shoots with no clusters mostly. If I cut a shoot with a cluster, I left foliage down the shoot from the grapes
I wouldn't prune unless absolutely necessary until the vine goes dormant, it just invites disease. The muscadine is a natural fit for more vigorous trellis systems like the gdc. However, if you are pruning in the summer then you can use those cuttings to propagate the vine, as muscadine will only root off of live cuttings.