Highest flowing CFM electric fan that ACTUALLY fits?

The shrouded 2 fan set up is restricting airflow when you have the fans turned down, thus running hot at all road speeds.
When you turn the fan speeds up and it cools down to 185* that means that your radiator and pump combo have enough cooling capacity to do the job.
You dont need a new radiator if you can cool it down to 185*
I would overdrive the water pump with a different pulley ratio and add a Hi flow thermostat to take advantage of that capacity and run the fans full tilt all the time.
If you choose a new radiator put in the biggest 2 core you can find. IMO Griffin makes the best USA made radiators, they are great people to work with and know cooling systems very well - no guessing games.

All of that is totally unnecessary, even by your own reasoning. The current water pump works fine, the radiator works fine, hell even the current fans, when running, work just fine and they allegedly don’t flow that much cfm. If none of that was true the fans wouldn’t be able to knock the temps down to 185* when they’re running.

And really, everything between 200* and 220* F is a perfectly normal operating temperature.

There’s a couple issues that haven’t been addressed. Why aren’t the fans kicking on when the car is getting hotter than the OP wants? That’s a fan controller issue, the fans seem perfectly capable of cooling the car down. The temperatures rising, if they’re doing it on the open road at speed, would indicate an air flow issue. Especially since the fans can cool the car down. But how hot does the car get? Does it really just keep climbing in temperature? Or does it just reach it’s happy medium higher than the OP would like?