I would think that the JB weld or equivalent epoxy would work if the grooves aren't too deep. Ive used the Marine 3M stuff. I think it may end up harder than JB weld. The more permanent one requires keeping it damp / wet during curing.
I think if push came to shove though and the grooves were deep with the possibility of becoming cracks, Id look into having it welded and file shaped and sanded smooth. They're cast IIRC. Ive had good luck having cast welded by a local shop that knows what they're doing. Putting heat into an area that critical would be the only thing giving me pause. Properly done though is the key.
I too think the closed knucks are cool. Even cooler with a set of rotors on 'em!
