Hi Martin - We are in process of similar approach (Combined upgrade along with unicode conversion) with below details:
Source:
Release 701 (ECC6, EHP4), Non-Unicode
AIX 7.1
Database size: 3 TB
Oracle 11g
Target: EHP7, Unicode
What could be the tentative time lines we need to tell to customer. We do not have the opportunity for dry run/POC. It is 3 system landscape comprising of Dev, QA & PRD
Thanks
Vijay