Since messing with the instrument cluster recently, which means that I pulled the needles off and didn't get them back just right, I've been using my ODB to watch live data. That includes the coolant temps.
Even with only one 12" fan running on a fairly warm day (mid-eighties) and driving for about 15 minutes at 65-70, then another 10-15 at slow speeds, it never overheated. The coolant sensor I added turns on at 190°F, the temp will stay at 190 for a while before it turns on, and always turns on before it reaches 191. It'll turn off only after reaching 189 or maybe 188. The t-stat is a 180.
While driving, the temp stays between 186 and 194, never higher, and is more often between 190-192. This is with the stock radiator and only one 12" fan allowed to turn on via the sensor.
There is also a 14" pusher that came from my 2001 before I put it up for sale. It is mounted in front on the left (driver's) side of the AC radiator. It runs if the AC is on, or if I turn it on manually. When I turn the 12" fans off and turn on the 14" (with or w/o AC on), the coolant stays in the same range. The nice thing is it's quieter, which is nice in a drive-thru. It's not controlled by the coolant temp sensor, so I have to turn it off if it's not needed.
Because they make so much noise, I expect that eventually they will grow into 14" fans that will be quieter or they'll be returned until I find some that are.
Choose well, Grasshoppa!