Need help in finding best method of migration

[madhansun]

Hi Gurus
   I am going to give some estimation for my project and that needs some suggestion.
   My project is migration of Powerplay Transformer7.3 cube  to Cognos8.2 .
   I am having 19 models and 19 cubes in the Transformer now my client doesnt need of anything in version 7.3 he needs all the cubes in Cognos8.2.
   I am in confusion which is best method to do this migration process.
   First Method
     I can just migrate the cataog file into xml and then use this as a source for Cognos 8.2FM
     and i can build all the hieracchies and level by using the existing transformer model and i can publish the package and create some reports in report studio and do some analysis in Analysis Studio.

   Second Method
     Instead of migrating the Catalog file i can just connect to the database and get all the tables that are needed for the cube,then build the hierarchies and levels by seeing the existing transformer model.
then publish the package and create report using report studio and analyse the report using analysis studio.

Can any one suggest some pros and cons of this two methods and can you please suggest the best method.

Thanks in advance