Just about any of them require drilling. I thought about your approach, whcih could be done in conjuction with drilling and affixing to the rockers--for additional robustness, but there is no good way of making them stay without drilling and fasteners. I used SS nutserts and SS hardware to affix mine. Duffs used the nutserts on their units and claimed to have good success, so I stole that idea for installing my Rocker Rappers. Last fall, I was on a ledge and ended up jamming the rocker into a boulder and bouncing (sort of laterally) on it trying to gain purchase. The Rappers kept the rocker from canning, it did put a small bend in the Rapper and rocker AND pushed the whole rocker door post in slightly right at the bottom of the door level. Nothing that cant be fixed with a push from a pull-pal from the other side. Without the Rappers I would have REALLY screwed up my truck. I think this kind of product is best suited for a direct verticle force into the rocker. A strike from the side, with any of these products will likely yield a small tweak, but nothing comparable to a naked rocker. As far as a verticle strike, these things are bomber, which is probably more common.
I figured with the nutserts, it would look cool just with nice hardware in there...or I could install some polished SS or flat black flat-stock if I ever wanted to get rid of the Rappers. But after witnessing the benefit, I doubt they will ever come off.
Another crazy option would be to install a set with body panel adhesive. The rockers would have to be bare steel and could then be top coated. Ultimately, you are still limited by the inherent rocker structure however, and as I found out, if the rocker itself wont/doesnt move, then the whole lower side can. With the RR style, you could easily make introduce a set of brackets, bushings and use some tube to make a frame connection to help withstand such lateral forces...and I am considering this in the future, but 5K lbs, slamming, slamming, slamming into a boulder off-camber...somethings going to give...
The tube...like on Huess's units probably would have helped disperse the strikes better. I would definitely recommend those. Mine didnt, still dont have them...its on the list.
Go with at least a 3/16 version (1/4" if you can). If you play, ultimately you will pay...so better to have something than nada.