Pete;

...the sensor must sit low enough to be submersed in the coolant though, or else it may not sense when the fan needs to move additional cooling air...

Gert;

Which temperature sensor to use, and where, is a complicated thing which the engine design guys probably spend weeks measuring, checking, trying, etc. so just asking what the temp would be is oversimplyfying the problem...temp at any particular point on the rad is a complex thing influenced by a number of variables...that's why I'd just start out with whatever was stock for that engine in about the same location...naturally, an adjustable like Pete has will allow you to optimize...especially when the weather changes seasonally...

Cheers