Are these new molds? If they are they can be a little tight on the hinge pin. Use a drop or two of oil at the hinge pin then work it back and forth for awhile to loosen it up some. Also if your heating the mold you can get it to hot causing it to be hard to close. Like Wick and Fatman, I lay mine flat on table, I use a 6 inch piece of stainless spinner bait wire to guide my hooks in place. I just lay them in position and if they need adjusting I use the wire. Hold bottom half down and close slowly. I still get one to slip once in awhile. Practice,Practice,Practice. Just sit down and load over and over for a bit and you will get it. Did the screw that backed out go into the metal or completely through with a nut on the back side?
Proud Member of Team Geezer
Charlie Weaver USN/ENC 1965-1979