Shubova,
You may want to look at replacing the stock wheels with 4" du-bro's. I also modified the tailwheel so that is not attached to the rudder but has it's own servo, slaved to the rudder channel I also replaced the stock wheel with a 1 1/2 unit. I have not had a chance to check this modification out (too cold and windy) but it should help slow the tail wheel down.