Can't change default home directory using rstudio on rserver

How can I get rstudio to default to a different home directory? We have the same issue as described in this article but none of the solutions offered are appropriate.
I am looking for a way to force rstudio sessions running from rserver to default to a different home directory. At the moment it puts everything in /home/ which sits on the server root partition which does not have much available space. When large files are saved by rstudio they easily fill the partition and restrict access or use of the server.