I cannot give you figures but will tell you the gauge is 'damped' from the factory so it sits in pretty much the same place once OT is reached however, it is only when there is a serious high temperature event happening at the engine does it really move.........often too late!
There is a modification you can make to the gauge to correct this anomaly and something I did quite a few years ago, basically you need to remove the gauge cluster and cut out a couple of small electronic components and replace with ones that will allow the gauge to indicate correctly.
Have a search on 'MUD'.
Regards
Dave