Best Windows VNC client for talking to Mac Desktop

I am trying to display the screen of the secondary display of a Mac from a Netbook. Ideally, I want the functionality of the Mac "share screen" feature, in particular with this you can choose to view either one of the displays, or both together. Does anyone know of a Windows or Linux VNC client which does this? I have looked at a couple of clients (TightVNC and RealVNC) but they both show both displays in a horizontal scrollable screen. I'm also concerned about performance, in particular the impact on the remote machine i.e. the one using two screens. Are Windows VNC clients going to impose any more overhead than a remote Mac connected via "share screen".