The engine can withstand much higher temps than the coolant can.
If the coolant isn't boiling out then the engine temp is Ok!
Too many times folks look at the gauge and think it should be registering a little bit more "over there" and get panicky.
If a larger fan will fit on there then by all means go for it.
But don't get worried until the coolant starts leaving.
And the 190* thermostat is correct for most if not all of todays engines.
Big Jim

professional bovine relocation specialist