Help with Capri cooling

[Aether]

Ok so I am confused about some choices about how to setup the cooling on my v6 Capri. Since I have never driven the car it's hard to know what it needs and how far I need to go in setting it up.

So far I have just done the basics like checking the water pump condition and installing a new aluminium radiator. I was just going to install the standard fan since the engine is just standard but disaster struck and I dropped the fan while cleaning it and one of the fins snapped clean off.

So I thought I would get a thermofan. I bought a 14 inch fan which covered the entire radiator and that was great but there was very little clearance to the fan belt. So now I have a 12 inch unit which will fit just fine but I'm concerned if it's up to the job

14inch = 1060cfm
12inch = 850cfm

So I really want to get some peace of mind from people with more experience with these cars. Do they overheat? Is the thermofan a step up from the standard fan?

And the engine builder said i should just use water and not coolant. Does that ring true with you guys?