Never auto X-ed but I'm definitely a shifty-hands type.
But also, white knuckles isn't going to be good for actually getting someplace fast, even though it usually feels fast. clench your fists and your shoulders involuntarily tighten. I noticed this racing mountainbikes. and it made me crash a lot. If my hands were loose, so were my shoulders and i didn't crash as much. tight shoulders make it difficult to make the smooth inputs to the wheel that are so important in turning a good lap ( I think) and more importantly not crashing

 

Watch some WRC or FIA GT in-car. Steal what you see.