Can the TwinDolly and TrussDolly be used for high speed movements?

Yes, but what is high speed? Be aware that the dollies are standard equipped with skateboard-like wheels. So going up over 10 m/sec it is likely it creates a shake in the rig. We did use ┬áthe system once at a 4 m/sec speed using a fairly wide lens and still needed no stab head. (This is no guarantee… :-))