I wish I could remember the model, but a fellow in a club I used to belong to built a model from RCM plans and it had a seperate linkage to the tail-wheel. The rudder servo went to a bellcrank, and the outer end was to the rudder and further inside the bellcrank arm a seperate control rod went back to the tailwheel. The tailwheel then moved 1/2 as much (in degrees) as the rudder. It taxied as easy as any tri gear. Added a lot of complication, but it was a wonderful plane. Looked like a Kaos - low wing, bubble canopy and tapered rectangular surfaces - like the wings and empennage of a P-51.

Wrong plane for a beginner, but the "geared down" tailwheel may be an idea for the tail draggin trainer you're working towards.

I don't care for trikes. On our bumpy grass field the nose wheel roots and digs and inevitably gets out of alignment. They're easier for a "real" pilot as you can see forward out the windscreen on the ground, but for R/C I much prefer tail draggers. If my Contender didn't have widely seperated wing mounted mains I'd have converted it by now.

Related story: I was flying my S/K 50 a few weeks ago and the grass was a bit long. I could not get up speed for lift off - ending up waiting for her to take a bounce and yanking back to get airborne (a bad practice because if the engine quits you're toast). I was leaning back the engine, as it just seemed to lack power, to the point that I was flaming out at altitude when maneuvering. Turns out the wheel pants had each cracked along the forward edge at the struts. When taxing it was enough pressure from the grass to turn the pants in and rub on the tires. The faster I rolled the harded the "brakes" were applied.

Took the wheel pants off and problem solved.