I only ever fly off grass, and I recently retro-fitted a steerable tailwheel to my Extreme.

Maybe length of grass makes a difference?? But I hated the tail skid so much I never flew the plane after the first couple of flights for about 3 years until I fitted the tail wheel.

It IS possible to operate the model with a skid on grass, but I hate doing it. I like my models to look as graceful on the ground as they do in the air.

The Exteme with a tail skid was so clumsy bouncing about and ripping up grass that I just pulled the servos and receiver out and threw it in the shed.