on prior boats. I have used 3M 4000 UV on my current boat on all the hatches and deck fittings. The 4200 will yellow in the sun and look bad, the 4000 UV does not seem to do that. Everyone seems scared to death of the 3M polyurethane products, they really aren't all that hard to remove if you need to, and on something like a hatch this should be a rare occurrence. Don Casey makes a good point about not wanting a hair thin sealant line, you really want a bit of thickness to allow the two parts to move with thermal changes. One way to do this is to put something in the joint to maintain spacing - for example heavy pieces of monofilament lain lengthwise so they are imbedded. The problem I have with the "tighten later" approach is that you will invariably move the fastener when you tighten, and break the forming seal on them.