U Can Do 3D
BAS,
You don't really need 1/4 scale hinges for a UCD. The Great Planes "Pinned Hinges" work just fine.
archer,
I agree 100% about your tail wheel method! For the past 20 years, this has proven to be the absolute best way I've found to couple a steerable tailwheel/skid to the rudder. Here's a not so great photo of the steerable tailskid on my UCD.