I've had my XL for a couple months now and have been cooking out of it regularly. I've burned through the original gasket, and picked up a replacement high-temp gasket from my dealer. I also had a slight underbite originally, so I removed the top dome completely when replacing the gaskets.
I can't seem to get the domes adjusted correctly. I originally aligned the top and bottom with the back hinges/side hinges removed, then with the back hinges loose, I lined everything up so it fit without moving anything. I tightened these down, then installed the side hinges. After installing the side hinges, it seemed to pull the top dome back to where it was before.
I installed my high-temp gasket per the instructions, and after my first cook it was already coming off in several areas. It was also burned quite a bit from in the front from the underbite.
I re-attempted to adjust the top today. The problem seems to be that the side hinges do not have enough adjustment to them to attach to the top without pulling it back about 1/8 - 1/4", exposing that amount of the top/gasket to the fire.
Sorry for the upside down pictures. For some reason they downloaded upside down, and I didn't take the time to rotate them.