I set the 5'ers height to almost equal to the hitch when holding the hitch plate level. Maybe 1/8" to 1/4" at most below. I found if it has to ride up the hitch too much I had trouble getting it to lock. With a superglide you really don't have to worry much about high hitching. The capture plate on the 5'er won't allow you to hitch that high.
There is 2 separate clicks. First click the release arm pulls in most of the way but not fully locked. Nudge the tow vehicle back just a bit more and you'll hear another click and the arm pulls all the way in to the locked position.
My guess is that you are setting the 5'ers height too low and forcing too much weight on the hitch before its locked. If I'm slightly off from being perfectly aligned with the tow vehicle I do pivot the hitch just enough but thats only 1 or 2 degrees at most.
Unhitching I lower the stands, pull the release and raise the 5'er until I can see a 1/8" gap between the capture plate and the hitch plate. Then pull the tow vehicle forward and it releases with ease.
2014 Winnebago 26FWRKS 5th Wheel
2007.5 Dodge 2500 6.7L Diesel
2004 Dodge Durango Hemi 3.55 (Used to tow TT)