The Desann style is pretty much what Vader used. You can give it to your character in SP by either typing: 'setsaberstyle desann', or 'addsaberstyle desann'. The SP code even makes it more powerful than the other stances so it really does feel like Vader using it.
For MP there are plenty of mods that let you use that style but in a more balanced way.
I strictly play SP so that is how I use it, when the mood strikes me.