I went with Tyger Blades that are 6.6" wide - glad I did. Can't imagine a running board narrower than 6"
NERF bars or step bars work well at 4 to 5"...
Do you remember which model of Gorilla you use? Look like the 71631 would work being 12mm x 1.50. I get they're not perfect but provide a bit of deterrence.
Thanks!