I disagree with the premise that difficulty in latching and unlatching is a sign the hitch is not set up correctly. The real measure of whether the hitch is setup correctly is whether or not the front (steer) axle has been restored to the correct weight, and whether or not the trailer tows correctly.
Again I say it, jack the trailer and truck up high enough to take ALL of the load off the bars. It will then be easy to latch and unlatch. So easy, you can literally do it bare handed, no tool needed.
You are not hurting the truck at all to raise it up high. You are not hurting the trailer to raise it up high. The jack is made to extend, and as others have suggested, place a few few blocks of wood under the jack to give it a bit more reach.
