Sorry for the delayed reply, but I have been searching for some time to locate a source in your area for the Baby Jewel variety but was not able to find anything. I also don't believe there is another variety that will grow to just about 6 feet for your specifications. The Baby Jewel branches a lot making it a good hedge but that also means it doesn't grow upward very fast. You have other options for shrubs but more regular shearing will likely be needed.
Any hedge will require pruning to maintain its shape. I would not consider yaupon to be in need of more frequent pruning than most hedges. Two prunings per year is probably fine once it reaches close to its full size and thus is not growing as much. However in the early years there is much to do in building the size and shape you desire and so more pruning will be needed.
Hope this helps.
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