Similarly, I am not familiar with the Kubota RTV's, but there's no way I'd try it with my Rhino 450 (which is geared lower than the 660 or 700).
My experience is from growing up on a farm long ago, and from using garden tractors. For example, until Gravely came out with the Swiftomatic 2-speed gearbox, they offered speed reduction hubs to slow a "mowing tractor" down enough to use ground engaging attachments. Similarly Simplicity/Allis-Chalmers offered speed reduction pulleys for the transmissions, until they started offering variable speeds (i.e. sheaves) and hydrostat transmissions. Most mowing with tractors is done at about 3MPH (plus or minus), while most ground engaging work is done at about 1 MPH (plus or minus). Only ZTRs and professional landscape mowers (with faster legal blade speeds, BTW), get that mowing speed up over 5 MPH...
Ground engaging work is done quite slowly... and IMO, utility vehicles simply aren't designed to work at that speed, even if they are the pure utility type (governed to 25 MPH or less, like Mules, RTVs, etc.), or the utility/recreation type (like the Rhino or Polaris) that may not be governed so slow...
