You are saying you have 5 tables do you mean all 5 are fact tables which should be joined to become one table ???
ideally we should do an incremental load on the final fact table of your data model... Please find a link below with very good example of the incremental load script.. As a standard in Finance people follow the insert and update method of the incremental load process.. Link below .. hope this helps..
This link will help you:
It depends, what type of data do you have.
If the source data is a database table then query the timestamp dinamically and append the qvd.