Saw on tightvnc site that the java viewer also has scaling support like the Win32 viewer has. Tried to get it working from saiwaves. Copied the class and other files to /usr/share/vnc/classes/
Edited the index.vnc file by adding the scale factor parameter. But adding scaling causes the refresh to break - cursor trails everywhere - and also the auto scaling was not working in spite of using the open new window parameter. Probably because of the old version of vnc server running on saiwaves. So currently better to stick to no scaling on Linux.