I'm no off roader, but I'd think for there to be that much on top of a tire, the vehicle must be moving very slowly in deep dusty sand, or standing still with a lot being whipped up by the wind.
Another factor will be how much the rest of the vehicle has on it, to look right.
A few years ago we rented a cottage in the Outer Banks, basically all sand, and you drove on the beach a few miles to get to it. But that was Atlantic coast beach sand, rather granular and heavy. And a lot of it wet. So very fine dry sand gets everywhere, the coarser falls off unless damp or on oil/gasoline spills.
There is still sand under the seats and in crevices too deep for the shop vac!
At this point, I'd hold off on any step that would fix it in place, and wait to see how it looks with the body of the vehicle in place...
I love the hubs, and the rims, colour is great!