Yeah, I noticed the same thing with our ProPride. It was hard for me to tell if I had the tongue too high or too low. If it is (too high or low), then there's A LOT more friction holding the stinger in the receiver.
What I did was to line up the stinger EXACTLY with the receiver, then use a permanent marker to put a bold line on the shaft of the tongue jack under the tongue. As I'm extending it (raising the tongue), once I see the mark, I know it's now aligned. Just putting the tow vehicle in drive and letting it crawl (no gas) will pull the stinger right out! Of course, if you're on a ridiculously un-level site, that will complicate things, but at least it'll give you a good starting point.
Oh, and I totally agree that this hitch is amazing and pulls great. Good luck!
2014 F350 Platinum 6.7L Power Stroke
2015 Salem Hemisphere Lite 282RK
ProPride 3P Hitch