I have an 84 S & S and have never had any problem getting the bar on or off except for the first time I took it out after I bought it. After that I called the guy I bought it from who told me I simply was not getting the trailer deeep enough. Since then, I back the trailer down until the top corners of the front carpeted V are just barely sticking out of the water. At that point I can hand pull the boat far enough forward to raise the bar into place and secure with the winch hook which I leave loose until I get out of the water. I thn just take a turn or two to cinch the winch down. Obviously there is some variation depending on the angle of the lauch and your willingness to walk in the water to hand guide your boat, but I have launched it on several different ramps with several different angles and have never had any issue loading the boat. As for the binding issue with the bar, I say the same thing, sink the trailer further and pull forward by hand and it will release. Again, this is exactly what the previous owner told me when I bought the boat and got frustrated after my first in and out. He was right. I do admit that my whole method works much better if I have one additional person with me, but that is not absolutely necessary.
One final thing, if you have a concern that the hull will hit the jack, then either lower the jack during the loading process, or get a swivel jack and swivel it forward wile loading.