You have to reboot afterward. When the VM comes up it should hang at the windows logo ( You will not have console access ) if that happens, its using vDGA.
It might work some, but not reliably and several issues with the Tech Preview code. The code was locked down before the cards were available and new APIs to make them work properly were available.
The guide generally states its for K1 / K2 and is not really as clear about being for vSGA / vDGA as it could be. It also points to the HCL which states only the k1 / k2 are supported with vSGA, whihc is not the case. Most of our work has been on the Quadro cards.
WP