I also have the Biondo full size tree that uses the small, table top unit to run it. I had fabed up a wiring harness to allow me to unplug the trans switch and adapt it to the Biondo box. Set the big tree up in front of the car as far away as practical. Allows you to practice in the car using the actual tranbrake switch. You can work on ergonomics, technique, switch operation etc., in the driver seat.