So I picked up the Yakima LockNLoad Platform (60x54 size). I used the clamps to mount them to 2 of my 3 existing Rhino Rack Vortex Aero Stealth bars (very low profile). The front of the platform ends about 12-15" from the rear of the sunroof opening based on where I have my cross bars mounted. I also ordered the Yakima SkyTower feet, and might give those a shot instead of the cross bar mount. I am curious if having the platform sit a couple inches taller would make it louder or quieter. What is interesting is that the Yakima documentation stated that if you use 3 or 4 bars, or 3 or 4 pairs of Feet, you greatly increase the load capacity of the platform; however you can not order any additional mounting blocks (the blocks are the interface between the crossbar clamps & feet with the platform itself). I have reached out to Yakima about this, and they are working on a solution. Just be aware that if you order the cross bar clamps, they ship in pairs, not a set of 4!
With the cross bar mount I had to move the platform forward about 4-6" from where I wanted it due to the OEM mounting feet for the OEM side rails (if you look, the middle mounting location on the FX4 is beefy, and takes up a lot of room). I would imagine that with the SkyTower Feet you could move the platform back enough to allow the 80"x54" platform to still end right around the rear of the sunroof opening on the MAX trucks, but I haven't measured it to be certain. the 54" width is perfect and lines up nicely with the width of the roof.
The platform was light enough that I was able to lift it up and get it onto the truck solo, but a 2nd person would definitely help if you live in a quarantine free sector of the country lol. If you are gonna use a cross bar rail mount, I would recommend mounting it onto the bars while it is on the ground, then lifting the entire platform w/ bars, onto the roof. I did not do this because I wasn't sure if I would be able to access the locking mechanism of my bars with the platform installed up top - turns out I can access everything just fine and this would have saved me about an hour and lots of cursing and spilled beer.
Using the cross bar mounts it sits pretty close to the top of the OEM FX4 side rails. The platform itself seems very well made, and comes with a rigid plastic chin spoiler to help reduce wind noise and whistling.
Using Decibel Pro on my Iphone I am coming in right around the same levels of interior noise that I was running just the bars (around 95-105db @ 100mph, 85-90db @ 85mph - yes I am aware that speeding is illegal Mom), however the tone of the wind noise is slightly more noticeable. It's not a whistle or anything at all....just a constant white noise of wind rushing; similar to the interior of an aircraft cabin I suppose. It nothing that bothers you, and within 30 seconds or so of getting up to speed you don't even notice it if you are listening to a podcast or music, but I have the volume up 1, maybe 2 clicks, from where I was running just the bars (I was listening around an "8", and now use "9" for music and "10" for podcasts). It's definitely quieter than running my Thule 1600 box up top.
What was somewhat surprising is that I appear to be down about 1mpg from just the rails. I was not expecting that. Granted, I've only put on about 500 miles, up to my place in VT and back to NJ, but I was a full highway MPG lower than I was the week prior with just the bars (cruise control set for the Highway).
