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Now you've gone and peaked my curiosity about the subject again - RATS........
I see it uses tommy bars (what you called wrenches) like the Unimat 3-jaw does. They can be a pain if you use the chuck a lot. You may end up deciding to make a couple of pin spanners. or...make a fitting to attach it to your live center and you can support parts that don't or can't have a center hole.
Whew. Two of those wrenches is more expensive than the chuck.