$500 each for new (5-6 years old) 395 85 R16 XZLs and aluminium wheels seems like a no brainer if they just bolt on. Any reason to use the steel unimog wheels rather than MRAP wheels (assuming they fit).
the wheels fit perfectly but the ones I got from wartimefinds.com have only 90mm offset, 2.8" less than stock 161mm. They are 20 lb lighter even with beadlocks but and offer more stability due to wider track but will put added load on wheel bearings. If possible get XZL+ tires at least for the rear due to additional blowout protection, especially if you have a camper and run long distances at ~60 mph.
If you have CTIS you'll need large bore air filler fittings.
At the end I build by myself the studs , all I found was short for this wheels , because yo need to keep in mind this rims has not a conic centering, so if you use normal nuts they need Also some more extra lengh, My case is not 100% the same because I use adapters, but ....I use F124 steel to build It( the studs).
As You can see the std studs are ver short on the 6 lugs patern
Might be wrong, but I'm tipping they are the same size studs as in mine and my 'donor' prime mover (which has long studs to suit alloys..) How many are you after? I'd have 20 on the front axle. I don't have nuts tho as they are holding the late steels on my 1222AK. I do have loads of the older nuts with taper lock washer... The rears would be too long as it had dual rears being a prime mover. Whites Diesel are the people to try if you are down under.