Maximum percentage of salt

I'm a bit of a salt tooth, and I'm curious about pushing the limit of dough saltiness. One source I've come across said to beware of any recipe calling for anything higher than 2.5%, that it messes with yeast growth, but I've been making pizza dough at 3% with good results (it begins with a fairly high amount of starter, which might help) and I've heard rumors of going up to 4% and beyond. I did a quick search through the forums and couldn't really find anything on this question, and I'm curious what the thoughts here are.