I just bought a crossbed toolbox used off of e-bay. It is an extra deep box that goes all of the way to the bed floor. Since I have a bedliner, I cannot use the hook type things they sell for the boxes. Right now I just have 4 big self tapping screws holding it down. I am concerned this will not be strong enough when out on a trail as the box is full of stuff and very heavy. I wanted to bolt it to the bed floor, but am worried about it not being water proof if I do that. I can just add more screws through the bed rails, but am worried it wont be enough. What do you all think?