Fuji
I cant see how the gyroscopic mass of a radial can be much more than eny other engine after all it has a very short crankshaft that would be lighter than an inline engine but is likely to have an extra cylinder...........however if you are thinking of a rotory engine as was fitted to aircraft in WW 1 I would agree with you as the whole engine assembly turns on this type of engine and the crankshaft is fixed to the airframe.
As for taildragers swinging when the tail is lifted I think that this is due to the reduction of A of A on the down going prop blade and thus the thrust line moving towards the center of the prop , this is known as assymetric blade effect.