Straight from BOL (Books OnLine) ...
SP_updatestats = Runs UPDATE STATISTICS against all user-defined tables in the current database.
sp_fulltext_database = Initializes full-text indexing or removes all full-text catalogs from the current database.
SP_fulltext_Catalog = Creates and drops a full-text catalog, and starts and stops the indexing action for a catalog. Multiple full-text catalogs can be created for each database.
May I suggest you read in BOL about each of these SPs in order to assign the appropriate settings/parameters to each SP so that it runs correctly.
As to how long each shall run is dependant on my factors including, but not limited to, the power of the server/system you are running it on, the size of the tables the catalogs are being built against, the complexity of the catalog, the number of tables that are to have catalogs built on ...
Thanks
J. Kusch