You might also want to consider reinforcing the shock mounts. I'm not sure how strong the 80 series mounts are, but very heavy trucks wreak havoc on shock mounts when on long stretches of dirt/washboard roads. Also, you might want to think about mounting the rooftop tent towards the *front* of the roofrack to balance out the load, since that would place it between the two axles rather than directly on top of the rear one.
Also, some people complain about the visibility but if I had a choice, I would put the spare tire on the passenger side rather than the driver's side to balance out the constant weight of the driver (and IIRC, your freezer/fridge is mounted on that side also, isn't it?).
Editor, South & Central America
'99 UZJ100 Toyota Land Cruiser