ZenAtWork Yessir. both arms can be rotated so they point skyward. This removes the only impediment and they can be slid toward the non-blad-side of your fence. In the case of my Delta, when so repositioned, they are about an eighth behind the face of the fence, allowing tall items to slide unobstructed. If you're attempting to use something like a sliding sled or jig that hooks OVER the fence, both arm roller assemblies can be slid entirely off of the fence as well, allowing you to leave the tracks they run on in place while still removing the obstructions to movement. Genuinely: I use these daily. And while I'd never suggest them as a replacement or surrogate for a riving knife, I admit I DO use them occasionally as such. Won't stop your stock from binding with the release of tension, but DOES prevent the kickback.

ZenAtWork I love that people are so scared of modding their tools. Look: these things will ride higher than your max blade depth. They can be swung behind the fence if you're cutting a box or something. And in all cases when you ARE using a fence for stock, you SHOULD be using them. Make sure they're installed parallel, and epoxy the damn things if you need to. I don't foresee myself ever needing to UNinstall em unless I sell the saw, and then only so I can use em on the NEXT saw.

ZenAtWork Each unit is 2 inches wide. Exactly (per my Starett calipers). Each is 14 and five eights long. The arms sit about an inch over the base, which is itself a quarter thick (with the rails themselves sitting a half inch proud of that. Look: they're every bit as quality as the Jessem's, and you'll have the same issues fitting them. Save yourself the $125 and just get these. You'd never know where they came from, the quality is so impressive. You can use it to buy me a beer if you're ever in Kansas City.

ZenAtWork The company asserts 25mm (1 inch). In practice, a hair less, unless you wanna adjust your bit midway through the operation. Bear in mind: this is approximately the same depth as a domino mortiser. And, realistically, the only reason you'd want to go deeper is if you were using this for a structural component. Which this is not the right tool for. So don't do that.