I decided to go with the 4lb, it is stronger and should take the shock and impact better from the waves. I will also use it to foam in around the one way and for filling in under the gas door. I'm also going to get a gallon of their epoxy and hardener, way cheaper than the West Systems.Lookin' good!
Which 2 part foam did you decide to buy?
I just finished sanding the bottom of my hull. I didn't get as far as I wanted by today, but maybe after feasting, I'll go back out and try to install my check valve.