I'm a little behind on the times.....still using Solidworks 2003.
But, I've played around trying to make dimpled / flared holes in Solidworks and I found one way... though it may not be the best way.
For the part picture I've included below I made my rectangle sketch then went to Insert, Sheet Metal, Base Flange then specified material thickness ex .0625".
Next added a couple circles with the dimension of the start dimple/flare from flat then cut extruded the holes.
Then go to either the side or top profile of your hole and draw a centerline so that the following features will be located on the inside edge of your circle and not "floating" on the top or right side plane. A tangent arc can be drawn as your radius and the a line for the flat raised part of the dimple.
This is a quick dimple die without accurate dimensions just to get the idea across.
Next I made a centerline to revolve around.
Exited sketch then went to Insert, Surface, Revolve then specified 360 degrees.
Here's a close-up of the dimpled sheet.
Good luck with your roof rack, I'll have to keep an eye out for it here on OFN.