I believe Titan made the wheels for Kubota. I agree with Hay Dude, cast center wheels are the way to go. Both mine came with cast centers and with the cast centers, the lug nuts are actually shouldered with a short cylindrical piece that indexes on the hole on the cast center. Never had issue one with either of mine. My fronts are still stamped steel but the mounting holes are chamfered and the lug nuts have tapered shoulders.
Nice thing about cast centers is no ballast liquid needed. The centers weigh about 400 pounds each.
I do check the prevailing torque on the fronts infrequently. Just like automotive wheels, they can back off.
Kubota wheels index on the raised hubs but when mounting you still need to have the wheels off the ground and wiggle them a bit to insure they seat on the wheel studs properly.
Far as JD goes, they mount the same way as Kubota.