I use the Sulliavans on all my taildraggers. Sometimes the back end of the fuselage can be pretty thin in which case
I cut a flat piece of aircraft ply the shape of the white plastic and just thick enough to allow mounting of the blind nuts. Then I glue the ply to the bottom of the fuselage and after the glue has set use a small bit and drill through the blind nuts to allow the small bolts to thread in past the blind nuts and into the fuselage. Never had a problem with this set up. BTW, my field is rough grass so I always use the stiffer spring that is supplied for the steering.