Just wipe them down with a little silicone spray and wiggle them in. In my case, I used a little bit of my G96 CLP gun cleaner lube. Or you can try spit on them or use a lil soap.Yes, the eTrack clips work great. They do wiggle a bit when they are inserted, but they are mechanically sound. There are dozens of eTrack clip options. Just do an internet search.
I find the BoxLink clips provided by Ford to be a little too bulky - and, I still haven't been able to insert them because the tolerances are too tight. It appears I will have to dremel them down a bit to fit into the slot.
(By the way, this picture is of the clips at the back end of the truck bed, near the tailgate. The black channel descending downward to the truck bed is the latch mechanism for my SwingBox.)