If you're really just wanting steps, I'd think you'd want them at the lower angle.
What you REALLY need to do is call and talk to Richard. He's as knowledgeable as he is personable. He's a 3rd gen owner, just like the rest of us, he just also makes badass sliders.
Richard knows his stuff. I had the same question, I expressed my concerns, and we talked for probably 30 minutes about them. He recommended the lower angle ones, but I really wanted the tucked in. In the end I went with the ones tucked in and they work great for steps. My wife and kids use them just like a running board
Do the lower angle ones also stick out a little further from the body, to provide a little better protection?
The difference would be .15" of "better protection" between 7.5* and 15*