I have been using something similar for years, an arbortech attachment for an angle grinder. I have chased rings staying at least one ring away from the intended ring. I mainly use it for carving bowls, and dishing out seats for chairs. One of the more dangerous tools for sure and demands plenty of respect.
If your not already doing so use plenty of protection like a good face mask for dust, a face shield for eyes and muffs for your ears. Green wood isn't too bad, but the dry stuff can really mess up your lungs, sinuses.
Arbortech has an adjustable polycarbonate shroud that encloses the blade, so only the minimal exposed area of the blade shows, makes the process a bit safer.
Hamish.