If the plans show where to mount main gear for a tail dragger, that's the hard part. It should go ahead of the CG, right? Not a whole lot forward - but forward. I'll tell the story of the evil-handling old-timer I had - wouldn't take off cuz of ground-looping...the gear was too far forward.

Anyway - the old-timer had a skid for a tail'wheel'. It landed so slow that nothing else was necessary, but you had to lift the tail with prop blast and down-elevator to turn the plane.

My Balsa Stik - all I did was purchase a wire tailwheel (DuBro?). The wire from the tail gear was stuck up through the pivot, then bent back to lie alongside the rudder, then 'sewn' onto the rudder with copper wire.....easy-teasy.

My Goldberg Cub used springs from a rudder-pivot arm setup to steer its Klett tailwheel. That isolated the rudder (and its servo) from bumps.

A bigger rudder? Nah - not in MY book. Real planes are taildraggers!