The only time it was tough for me to get the header bar attached was when it was new. With my left hand, I push the header forward while trying to thread the screw with my right hand. Some days it is harder than others, but I can usually get it on. Might become a real pain once it is autumn here in MN, but that is when the hard top goes back on.
BTW, do you have a lot of wind noise coming from the front driver side corner? Did you solve it with some foam tape?