With my scanner I can watch the engine temp cycle between 180 and 214 without the dash gauge moving much at all,,
Pretty common that dash gauges have "dead bands" from the factory on purpose..

On VW/Audi/BMW, they do it to make them stay steady a the optimum display and it only moves when things go bad,
on a BMW you can program the dead band out and watch the gauge cycle with power output..

 

Wayne Dempsey's book "101 Projects for your Porsche 911" p.127 says factory thermo begins to open at 187 F and is fully open at 210 F, and LN Engineering low-temp thermo starts to open at 160 F and full open at 180 F. Your operating range matches factory thermo so presumably that's what you have.

I think engine operating temperature will be when the thermo begins to open, so with low-temp thermo engine operates around 160 F and with factory 187 F, which is a huge difference. A little cooler running will seem to allow the engine and radiator to last longer, maybe 175 F would be ideal for powertrain longevity and horsepower.

On Amazon I see thermos for other vehicles at 160 F, 170 F, 180 F, and 195 F, so there is quite a range and it seems being in the middle would be ideal.

 

Just like with other cars, Porsche engine design engineers had to account for a wide range of ambient air temperatures that the cars will run in, such as maybe like from -20 to 115 F. So I think your comment that "somewhere in the middle" is about the best one can do. I can see where running a low temp thermostat in very high ambient temps might work out okay. But if your running below freezing ambient air temps, the car may never come up to temp.

Back in the day when I was in the Navy and had my MGB, I traveled across country six times with that little car. One day I would be in VA, nice and warm. Then several days later I would be in the mountains and it was freezing and snowing. In order to keep enough heat in my radiator so the car heater would work, I would block off part of the radiator with cardboard...sometimes blocking almost 50% of the air flow. I remember seeing the truckers doing the same thing.

 

I had a 1978 MGB ,, despite replacing all the parts of the cooling system it never worked particularly consistent..
I too had to cardboard-up in cold weather. Love-hate with that car..


In track cars, with AL heads and blocks,, my across the bpard experience is that 180 is a
nice safe ceiling,, above that at high revs, things get mechanically awkward at times..
A engine set up at 180 peak seems to just hang together better than those runing 205 to 215..
Not scientific here,, just observational...

 

I would think even more so...