Not much you can do with the collectors. Looks like the flanges are bent. You will never get a seal to stay in there. Keep the aluminum ones or cut off the collector and change flanges.
Stock printed metal ones last the longest for me. Good bolts help too. So do good threads. Put the metal to the header side. the last set I used is going on three years. I even use them and gasket match the port's to fit my race engines.