Roof rack crossbar location?

[DLG8]

Does anyone know the significance of the little dot and arrow on the top of the rack and crossbars (CB's)? The CB's are currently aligned to these marks. The CB's can be repositioned so I don't know why they are there unless it is to make sure the rack is square when installing.

I'll need at least 24" spacing when carrying my kayak.

Any thoughts?

[CanuckNoTruck]

The marks indicate the optimum position to reduce wind noise. There is still noise, but it's acceptable at those positions, elsewhere it is really bad. I've had a kayak on mine, it's pretty noisy.