I will be honest I made booboo I didn't let the silicone cure all the way and I didn't sand the edges so I had a mess lmao, the rubber coat held pretty well, and about a hour later water came through the silicone on the edges, I used blankets to soak it up and thank the lord up above I was able to get it all cleaned up, so game plan is spray some more rubber coat and do a sanding along edges just to make sure I don't get a leak again. As far as structural integrity, I learned that stuff way back in middle school with popsicle sticks, basically we had to build a structure with the least amount of popsicle sticks, and my structure was the best, its all about distribution of weight, in this case distributed the weight at the corners, there is no bow in the middle because the corners are taking the majority of the weight and I used 3 different supports one on the bottom and along the bottom, and one in the middle, and then one at the top on the side and along the top. My goal was to go as light as possible because I live in an apartment and don't want to much weight on the floor, I was sort of scared when filling it but the floor seemed fine.