There are no 'options' defined. The use of WTPUB:// is strictly up to you and your company and what information you want staored in Windchill versus on a shared disk location.
The only WTPUB:\\ I use is for pro_format_dir. Formats need to be in Windchill so they don't come in as new when creating a drawing.
Most of my config.pro settings for directories (pro_*_dir) point to an environment variable we have set named ptc_cfg_path which points to a shared folder, x:\ptc_settings. My config.pro entry for the symbol library is:
ptc_symbol_dir $ptc_cfg_path\symbols
If I moved the symbols into Windchill, the config.pro entry would be:
ptc_symbol_dir WTPUB:\\PDM\Libraries\CFG Lib\Main\PTC Settings\Symbol
The 'PDM' is the name you use to register the Windchill server to Creo. It MUST be the same for all users.
The 'Libraries\CFG Lib\Main\PTC Settings\Symbol' is whatever you have defined for your Windchill Library structure.
Hope this helps explain how to use the WTPUB in a config.pro file.