I'm finishing up the BUSA 1/6 N17 with fully flying rudder on pull pull. Not a big deal to build out. I read the bottom of the FF rudder is attached to the skid support. From the pic above I cannot tell if the pivot line is vertical or leaning forwward a bit. Either way it seems one would solder two small brass tubes vertically in two places. The skid touch point and the rear of fuse where it meets. Piano wire attached to rudder (L at top) slips in tubes with wheel collars..one below fuse (out of sight) and other top of skid, recessed effectively hidden. I was looking at the aerodrome versions today- EZ and undercambered wing version.