I pondered adapting an existing tiedown to fit the Mav rails, and was glad to see this post. I did the same with the exact tiedowns but with a slight change. I replaced the M8 bolts with M8 thumb screws (with a 3/4" head to fit the available space in the tiedown), making it easier to relocate the tiedowns on the rail with the turn of a knob. Total cost under $20, plus a little labor.I just installed 4 of these.
https://www.amazon.com/gp/aw/d/B082YTZS6Q/ref=ya_aw_od_pi?ie=UTF8&psc=1
They are almost a direct bolt-in for the factory accessory cargo rails, but you’ll just need to file/grind about 1.5mm off the four edges of the two crescents on the backside which inserts into the rail tracks (see pics).
I used a course RASP hand file which allowed me to remove material at a fairly level/straight manner (filling two edges at a time). If you have the proper tooth count blade, you might accomplish this with a hacksaw too. Then if you want, you can shoot some black paint to cover the exposed aluminum edges, though they’ll be hidden in the track.
The steel “backing plates” which clamps these hooks to the tracks (inside the tracks) is a nice full height fit - you just hold the plate vertically with your finger in the track as you snug it up until the plate rests between those two crescents, which will then keep the plate in place as you final tighten.
I simply installed these at both ends of my tracks - the forward ones right about where the factory tie-downs used to be before installing these tracks. If you need to move these along the tracks, just loosen slightly and reposition. And if you prefer not to use that big FORD partition, you could even get 6 or 8 of these hooks and use these exclusively.
This is one of the “crescent” edges that must be filed/ground down slightly to fit the tracks. NOTE: File EQUALLY each of the 4 crescent edges so that the end result is that the hook assembly fits CENTERED vertically in the track!
