After seeing your note, I called them and learned from their phone rep that the fruit are no bigger than 1/2". Making it both seedless and (almost) grapeless. On the other hand, a member of the Southern Fruit Fellowship reported that they had a group meeting and tour that involved seedless muscadines being grown in the state of Mississippi.

All my seedless grapes lasted a few years and then died for whatever reasons (winter, disease, etc.), although a few were delicious, the clusters and grapes were small, and all things considered i was reasonably happy with store purchased grapes. I have had an Isons muscadine and scuppernong a few years which are "care free" and have a tough skin/seeds, but delicious flavor as they are indigenous. For a treat try Isons bottled red or white muscadine juice which they will ship.