BW Upgrade 7.0 -> 7.3

Hello friends,

in the near term is a project in which we upgrade our BW system from version 7.0 to 7.3. It will migrate all existing data and stack be but the stacks should be seperate.
Now, I raises the question what should I do.
Currently we have a dual stack installation. We want to separate the two stacks.

What's with the DB? Will be installed on a separate server or on the ABAP stack?

Here are a few points to planning:

- Installation/Upgrade BW 7.0 -> 7.3
- Splitting of the dual stacks
- 2-3 SUSE Linux Enterprise 11 (64bit) server
- Migration of DB and all data files
- After splitting, migration of the stack (ABAP + JAVA) on separate servers

Since I want the existing DB and stacks (separated) still use makes me wonder if I just a pure SAP installation on the BW7.3 Servers do and then start the migration, or what should I do otherwise.

Is there BW 7.0 & 7.3 installation guides and a migration guide from BW 7.0 -> BW 7.3?

Experiences and opinions I would be happy.
Hopefully creates a lively discussion.

Thanks and best regards

Michael Kilens