[Admin] Reclaim Space from 4 TB Database

Hi Experts,

Greetings !!

Background -  PG version 9.4

Linux - Rhel

I have a scenario in production environment where the DB size is close to 4 TB and couple of tables are 1.5TB each. 

Now, as the table are highly transactional therefore there is lot of bloat in tables. While I run Vaccum Full in weekend when there is no incoming connection, vacuum full never completes in 2 days. 

Firstly, I wanted to know what are the factor I should consider to speed up Vacuum Full process other than investing memory. 

Secondly are there any other option to reclaim space.  (Pg_repck is a option). I am looking for more option if available. 

Thank you everyone.