EN48 asked, " It has been my understanding that the Delta hinge is used also to reduce flapping amplitude so that the TR can be placed closer to the tailboom without striking the tailboom. Do I have this right?"
Not really, since the TR must be placed beyond the maximum flapping range of the blade in any case. The delta hinge cuts down the flapping forces that are caused by disymmetry of lift in forward flight, since without it, the TR blade would flap to the stops and create large forces.