I used kosher salt that I weighed out, I think it's just a personal preference thing.
Do you know if a low hydration level would cause the bread to be weaker? I'm think that maybe because I heated the water mixture and then let it cool on a countertop, maybe a significant quantity of water evaporated (though this seems unlikely). Should the dough be tacky at all when it's done kneading? Mine was pretty dry when I shaped it and put it into the pan to rise.