That sounds a good shout there Nick! If I can adapt a design, then it's solid really. Would rather get it first time but the way I see it is that bearings have more moving parts, therefore there's more to go wrong. That said, pushing the bushings that far over their intended speed could induce failures still...

I think I might up the disc width to 20mm instead, which may leave more room... Needle rollers sound a good option though, if they're cheap enough I can definitely stock up on spares if that's the case. Will get on the CAD programs, get designing it and see what I can fit in, probably the best bet here!