While I had the headliner down for my radio fix, I went ahead and drilled 3/8" holes in rooftop to install my roof rack supports. I used Kindorf slotted strut 1.5"x3/4" I cut them 4ft 2in and painted them black. I used some rubber gasket material cut to size of strut made holes for the bolts to tightly go through. I put silicone gasket maker on both sides of the gasket material between roof top and strut. I used all thread rod and 3/8 nuts and washers from bottom to top and then die cut excess off top when done. I tried using bolts it was much harder. I used 3/4" conduit as cross bars with 3/4" pipe strut clamps, painted them all gloss black. when I went to install the Yakima rack it was a little tight. I probably could have made it work, but decided to go ahead and cut some 10" strut pieces and attach them to raise the cross bars up so the rack is not riding against the roof. I used channel nuts with spring 3/8" and 3/8 m10 cap screw bolts 8 (2) on each 10" piece. In the end I am happy with the look. It has a lot of flexibility as far as moving the cross bars front to back as needed for other accessories. I could even always make longer cross bars to mount other accessories on the side of the Yakima rack. That reminds me I cut these cross bars equal the the width of the rack. I put 1/2" knock out caps on the ends cuts wind noise substantially. Just had to crimp the caps some then they tapped right in with a hammer. I also relocated the Yakima wind deflector by flipping the mounts to lower it also substantially decreased wind noise from hitting the mounts to the roof.
I also made a tire mount with an 8" piece of strut and two 8" pieces of all thread rod and 4 nuts and washers.