I think you have to install SO with the switch "-net" to install it for more users. Please read the docs for more information since I am not completly sure it isf is -net or /net or something else.
Then you have to run setup for each user which takes about 4MB per User. I hope this helped a little. Bernhard PS: The location does not matter but I think /usr/local/soffice would be ok. Of couse you have to symlink /usr/local/soffice/bin/soffice to /usr/local/bin/soffice
