Regarding the studs, I am using the original ones on my U500 with Hutchinsons. 3 threads are showing inside the nut, but I am using sleeved lug nuts that have about 4 threads below the level of the wheel face to "compensate". They maintained their torque of 600 N-m over a 45000 km trip last and this year.You will probably find it is cheaper to get them from Mog Central or Unidan here in Australia, they buy them with the 395/85R20s by the container load, so the transport costs are shared over 40 or 50 wheels. No matter what, you will still be up for the import duties, GST, port fees, etc etc.
You also need the longer wheel studs, as the stock Oz-military wheel studs are too short for the Hutchinsons.