Haven't used these specifically. Used a similar false raingutter bracket from Thule years ago to put a rack system on a Leer topper and those worked great and I had no issue with them supporting the rack and gear. You are putting holes in the vehicle's sheetmetal so they are pretty permanent and the key, I would think, would be to locate them in an area where the anticipated load on the rack could be supported by the area where the brackets are mounted. Getting an proper seal would also be critical. Maybe someone else will chime in here also.