RE: Taxing.. Look out!!
You can adjust the tension on your wheels so they don't roll as easily. Put a little bit of fuel tubing in between the wheel collar and the wheel on each wheel of the plane, then push the wheel collar tighter against the tubing to adjust the tension on the wheel. This will help keep the plane from rolling as easy, but you'll still be able to roll for takeoff. This will also help slow the plane after landings. You still want to try and get your idle lower too, but this will help you fix your problem.
Hope this helps
Ken