Paul,
I just took some measurements and have attached a diagram of the roof layout.
The red strips are the roof rail "finishers", which in stock form are just a solid trim piece that covers up the holes for the OEM roof rack (see the photo of the actual roof). These would get replaced with parts that have cutouts for access to the holes for the OEM roof rack. There are 5 holes on each side, 1 roughly in the center and 2 near each end. The total length of these strips is about 79.5". Approximately 5" at the front slops sharply down to the windshield and 1.5-2" of clearance is needed for the rear hatch to open, leaving a usable length of 72-72.5". All 5 holes are within that 72-72.5" area. These strips are 1.75" wide.
The section marked "Hatch Area" is the top section of the rear hatch, which is essentially part of the roof, and comes forward a bit when the hatch opens.
The orange block is the satellite radio antenna.
The big white area in the middle is essentially a big window in the roof, part of which is a sunroof.
The 2nd photo is a picture of the actual roof looking from the back of the vehicle. Unfortunately, I wasn't up high enough to show everything, but should give a good enough idea.
I also measured the width from outside edge to outside edge of the trim finishers and came up with 51.5" in the center and 51.25" on the 2 ends, so since the finishers are 1.75" wide, it would be 49.5" - 49.75" center to center, assuming the threaded holes are centered underneath the finishers.
Given these dimensions, the 72" rails and 63" platform would probably be the only combination that would work. The 63" rails might not be long enough to get access to all 5 threaded holes and I think the 79" platform would just be too long as it would need to extend an inch or 2 in front of the windshield to leave clearance for the rear hatch to open. If they had a 72" platform, that would probably fit perfectly.
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