You can purchase those balls and ball connectors new from TRF.
When fitting the vent lid I get new screws that are an inch long, so I can hold them better and get some wiggle room with the screw when it is a ¼ inch in the hole, but before that I chase all threads, so I can turn the screws easily by hand. Put the gasket down first and it does not have to fit correctly right away you can move it around just make sure the screws go through the 2 holes in the back of gasket. Do not worry about the spring you can put that in last. Put the 2 screws on the vent lid hinge in back first holding the vent vertical and leave them lose. I then put a point on the rod tip so it slides through the connecting barrel hole easier. Next take the connecting barrel “or whatever the link is called that the rod goes through” and put an inch screw in the back of that, so you can hold it as you fish it in place plus the screw is for pinching the rod. The barrel goes through the thin side of the sheet metal piece of the main leakage usually coming in from the driver side unless someone has flipped stuff around; there is a thick and thin side. If not fit this way around, the hole in the barrel will not be in the center of the leakage mechanism so the rod can be in the center. Now slid the rod into the hole on the barrel while your hand is in the vent hole lining up the hole in the barrel with the rod. Once the rod is in the hole of the barrel, snug the one inch screw on the barrel, so the rod will not fall out. Next while everything is still lose flip around the front linkage mechanism and put the 2 front screws in place with ears point up and on the edge of the vent hole. Now everything should be hooked up and lose. The finale adjustment is next where you slid the rod deeper in to the linkage barrel so that with the knob on the rod you can measure about 2-1/4 inches from the center of high point on the knob to one of studs for the tonneu cover that way the leakage has the correct amount of travel. Now snug up the 4 screws starting with 2 in the back. Hope this helps.
steve