VS Series III 5L, Auto, Ok, I have now fitted a single 16" Fan and all is operational. You wont get a bigger one in and nor do you need it.
There is already a fan for the airconditioning condenser. So i decided I only needed one fan engine side of the radiator.
I purchased a 16" fan from supercheap auto and a (Davies Craig) thermal switch assembly and relay. $120.
I can provided photos and advice to anyone wishing to do this. The wiring is really simple but I am a technician if you need help.
When I pulled the radiator out, this is required to mount the fan more easily I found mass amounts of debris in between the condensor and radiator. In hindsight I believe this was what was making my car run hot after all.
I could not see daylight through the radiator.
All that aside my temp dial is regulated to just above the second graduation on the cabin dial. It has not gone above there since the changes.
Hope this is helpful. Cheers.
PS I can barely hear the fan and the engine is slightly more responsive.