HydraRaptor made a Darwin corner bracket in 50% filled ABS this evening: -
It took 2 hours 35 minutes. It feels pretty sturdy but there is some delamination through the thin section of the corner facing the camera. A bit of a weak spot in the design I think. Also the base is a bit warped as I didn't use a raft. I don't know if these matter as I haven't worked out what all the holes are for yet. I need to make seven more for a Darwin. I will probably do a 100% version for comparison.