I have my hatches cut and am just about ready to fiberglass the lip. I seem to remember reading a posting that said to place a piece of cardboard on the outside of the hatch cover and then tape the cover in place. This would recess the cover a little to compensate for the additional height created by the gasket. The thickness of the gasket would determine the thickness of the cardboard. Have I got this right? I was looking at some 7/16" gasket material from CLC and would guess this would compress down to about 3/16". Also, is it wise to fill the crack between the hatch cover and the hull with wax to keep resin from filling it when you fiberglass the lip? My first boat and I'm a little gun-shy. Thanks in advance.