What exactly are you looking at ? Are you trying to setup replication and log shipping on the same machines for the same databases ? Is so, why do you want both the options.

Please provide with more info. to help you better.

What is the size of the database you want to duplicate ? What is the purpose of creating a duplicate ? What is the load on your OLTP server ? Is the secondary server of the same config. of your original server ?

--Kishore