I didn't really like the KCmodels links (some were ok but most had too much slack) so I went for Traxxas #5347 instead.. 3mm Ball bore and M4 inside the shaft. I did not use the 3DR rod adapters but went for 5mm OD / 4mm ID carbon tubes and M4x16 set screws glued into the tube ends.
45 deg (actually a bit less with #5347) works just fine for a print radius of up to 80mm.
45 deg (actually a bit less with #5347) works just fine for a print radius of up to 80mm.