Sorry for the delay - our current configuration is as follows:
Relase 8.5.3 client running in multi-user mode / Data location on network share (dedicated site with individually mapped folders per user) - currently using these options for installation: setup.exe /v"SETMULTIUSER=1 MULTIUSERBASEDIR=Z:\ MULTIUSERCOMMONDIR=c:\Lotus\Notes\common"
What we are trying to accomplish is to use the browser plug-in referring to the networked share location for the data files. I assumed that would be accomplished by entering command lines for installation (similar to full client installation) - I did see the comments left with some command line options but have not tried as of yet. I was also looking for documentation of the different commands for the browser plug-in installation so I can compare to what is available for the full client