Since yu are not ujnderstanding i have enclosed a photo. In it it will name all the parts. Nothing to do with the roof or the rack. The rubber on the glass of the roof is not to keep water out , but mainlly wind and sum water. This is teh reason for the roof drains. At each corner inside of the sunroof are drains, at the drain are attached to drain tubes , the they run down the pillars of the car. The 2 frunt run down each pillar and the rear down the rear 2 also along the widescreen.
They run all the way down , in the frunt they run down to an area behind the frunt fender ducked between the panel. The rear run down into the area rear of the rear wheel well. The 2 frunt drains are the largest and drain 70-80 percent of the water. problem is that if yu live in areas that are dusty , have lots of mud or trees or debreed areas or snow areas , the drains in the frunt tend to get blocked , clogged by dirt and debris that gets splashed into that area frum the frunt tires while driving. So teh water does not drain efficiently frum the roof drains , causing it to build up and leak at the top.