Please post code using the code tags to preserve indentaton.
Are you saying that if you replace the line
with a different sensor number the link works with the new sensor and the viewpoint? If that is the case then you just need to create four links for the four sensors. Updating the viewpoint position and orientation in the timer function is not necessary if you created a link between the two.
I'm not sure what you mean by using sensor 2 to replace the mouse.
Besides tracking the hands to you also have glove data for them? Either way you can add left and right hand models that are linked to the tracking data.