some of my partners have rode the rail and haven't flipped it, but they were small guys. our company has some larger mods that have room to move around the pt. on both side and i have been known to sit on the counter so that i'm in a better position for compressions. the only thing that i can offer is to do what works. around here you can hear it in the bays and in the front office "adapt and overcome" use your head and do what works, without taking risks that you are not comfortable with.