OGG initial load for huge Oracle DB

Hi, OGG gurus:

May I have some advice on initial load for a 20-TB Oracle DB, please?

DB size: 20 TB

Hosts: Solaris SPARC 5.11 (source), RHEL 7 (target)

Oracle DBs: 11.2.0.4 (source), 12.1.0.2 (target)

TDE: Yes (source), No (target)

# Schemas: 65

# Tables in main app schema: 2,938

Data types included: BLOB, CLOB, LONG, RAW

Maintenance window: 48 hours (during which DB can be down)

The key point is the DB size and maintenance window, while MOS Note 1311707.1 (Master Note - Oracle GoldenGate: Initial Load Techniques and References) doesn't give much idea on how big of the DB can be handled and how much time it may take.