WebLogic ADMIN Q

Q1. How to analyze size of one application?
(Like it is a Small, Medium, Large, Extra Large, Enterprise application)

Q2. Is it possible to run two NodeManagers at time in single machine if we have two weblogic middleware home directories?
(Like Oracle/Middleware1/......
         Oracle/Middleware2/......)

Q3. Steps to migrate older version to earlier version in weblogic?

Q4. Steps to migrate Dev Box to Prod Box?