That's what I'd do, but bolted on and wired up for a very quick changeover.
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I have falcon fans on my county, they are controlled by thermal switch that turns them on and off automatically, it screws into thermostst housing.
I also have an on-off-on switch so I can override the system to manually turn the fans on or alternatively turn them off for river crossings etc.
Falcons regularly travel over 300,000km without having to replace the fans.
Tridon make a wide variety of these thermal switches with different threads and wiring as well as temp ranges.
They are far more reliable than the probe in the radiator hose.
You will also need 1 relay for each fan and at least 40amp fuse.
These fans move far more air at idle and low engine speeds than an engine fan, around 3500cfm from memory.