I'm no expert, but from what I've read around different forums, it seems the normal range for TFT is between 160F-200F. When I google search "transmission oil temperature gauge", I get gauges with a temperature range of 100F-250F. Based on these findings, I think I have it right.
So to answer your question e350, this morning I drove for 30 minutes in 70F weather and my TFT was at 187F.