In the full size world the cyclic is pushed forward to tilt the rotor disk forward and just enough collective is brought in to taxii. The rotor of models generally isn't free to teeter because of the rubber bushings which try to hold it square to the drive shaft. But even so, you can get some amount of disk tilt. I'm pessimistic about getting enough tilt on a model. Softer bushings will allow more tilt. If you can't get it to taxii as is you might try the softest rubber you can get. The flight response may be less than desired but it might taxii on a smooth flat surface. But because of the limited tilt angle I'm thinking the model will be on the hairy edge of lifting off if it taxis at all, so be very alert cuz it may come off the ground with a full load of forward cyclic and that could be exciting.