I suspect my original O-rings did not weep fuel when I first installed them because I had less than half a tank of fuel. After adding more fuel, to ~ 3/4 tank, sometime in summer 2017, I started to notice a slight fuel weep from my cover screws but not weeping out the edge of the cover. I just replaced the original 70 durometer Buna-N o-rings with harder 90D Buna-N O-rings so I could torque down the screws a little more. The original 70D O-rings also were soft enough to squeeze out from under the screws more than I liked.
I also noticed that I had fuel on top of my cover gasket (under the cover). This fuel had to travel up the threads to get to this area since my cover gasket is a solid piece with no center hole cutout and I didn't have edge leakage. Since I had all the screws out to change the O-rings, I also added thread sealer to each screw as well. I'll report back on the results of this change once I get out sailing this spring. If I were to do it again I would start with just thread sealer on the screws and see how that works.