I'm a Canon shooter, so I don't have a lot of experience with the 17-35 on a D800. Those who have more personal experience will no doubt offer insights.
In fact, in conversation about this topic a few days ago Dr. Mustard offered that he preferred the 16-35 F-4 for this application. I said at the time that the greater length of the 16-35 and subsequent potential for upward torque with a large dome might dissuade me. But, if the 17-35 needs this much port extension, at least this particular 17-35, the 65-70mm port extension required of the 16-35 may not be substantially different if offering superior optical performance.
Not without variability because of slight alteration in change of position of slate, but in this series, PVL 60 was the best of the best. And I see the lens was inadvertently moved to 19mm instead of 17mm on the 60mm port extension test. But, checking for clarity of the type suggests more port extension is necessary for this lens than we had been assuming.
The PVL 60 is the best, which surprised me. I'd be inclined to do more open ocean testing if this was my camera and lens. Also, all of these were shot of F-7.1 at ISO 200. In a real life scenario it would likely be better to shoot a higher ISO to get F-11 or F-16 if optimal corner performance the goal.