lewmar hatch leak - mounting a new gasket

In the summer 2017 I sealed the hatch with some butyl sealant and sikaflex 295 UV but the humidity levels are now to unevenly so I change the rubber gasket to a new one. This is the first time I do a hatch gasket change so I don't know how tight it must be. After completion of the filming and editing I plan to make it more tight so the gasket will hold it self on the acrylic glass plate. I have measured the old gasket and it is 188 cm. long. The glue I used is Loctite ALL PLASTICS : http://www.loctiteproducts.com/p/sg_plstc/overview/Loctite-Plastics-Bonding-System.htm Rubber gasket : https://www.svb.de/de/lewmar-dichtungsgummi-fuer-low-profile-luken.html Rubber for one hatch : 38 US Dollars Loctite all plastics glue : 11 US Dollars