A G2 chordal fillet is what every product should be designed with, if only all CAD programs supported them better. 
To get one in Rhino, you use BlendSrf or BlendEdge… but not VariableBlendSrf (again, Rhino sadly isn’t very consistent)… however, since both BlendSrf and BlendEdge requires edges as input, while VariableBlendSrf does not, to get a chordal, I often start with VariableBlendSrf (DistBetweenRails), delete the result but keep the trim, and then replace with a BlendSrf (I hope someone can tell me a better way).
A great CAD package also allows you to set a minimum desired radius (and also tension). In Rhino, you have to do a curvature analysis after the fact and to a tedious untrim dance since BlendSrf and BlendEdge (unlike BlendCrv) doesn’t have an Edit command…