What you want to do is tell winswitch to use a specific command for 'vncviewer' / 'Xvnc', no need to change the source for that! This is stored in your settings which were detected the first time you started winswitch.
- You can change the vncviewer in the UI: 'Configuration' -> 'General' (tick 'Advanced Options' to be able to override paths) then go to 'Configuration' -> 'Protocols' and set your vncviewer path there.
Other relevant options, ie for shadowing existing displays:
vncshadow_command="/usr/local/bin/x0vncserver"
vncpasswd_command="/usr/local/bin/vncpasswd"
I will now do some tests with vinagre and vino server to confirm if they work properly out of the box (command line compatible with other binaries) or if I need to tweak the code specifically for them. Will post the results here.