Roof racks aint all the same... What is best?

[P4trol]

Don't forget there are two figures:

Weight the roof will support
Weight the rack will support

I'm sure there is some wally factor in there.

These are for driving, not parked up. So your rooftop tent should be ok.

The higher up your weight, the higher the vehicle centre of gravity. I notice this as soon as the spare is put up there.

The other limiting factor is fatigue. The heavier weights will fatigue the roof quicker. Rough terrain, to top it off, the worst.