"turbo cool down recommendations too ". It would be more accurate to say "for cool down timers only ". Knowing when to shut down the motor for turbo health IS the ONLY reason one would put a probe post turbo because that is all the reading tells you. Notice that every single gauge made is calibrated/marked for PRE turbo temp placement (1250F). The red (warning) markings on all gauges placed at 1250F are ONLY accurate if the probe is placed PRE turbo.

I plan on placing another probe @ the post turbo location because I plan to get a BD temp cool down device. But the truth is, a gauge is not really even necessary because the only numbers on the gauge that give me any usefull information are the 300-400F range numbers.

Our fire department diesel mechanics placed EGT probes in the post turbo location (with cool down devices) on our rescues because we were driving code 3 and then quickly shutting down the engines - we were destroying turbos at an alarming rate. This is the same reason big rigs have the probes in the post location. It has nothing to do with the engine, only turbo life.

So, detemine what you what to learn from the pyrometer. Are you concerned with;
Engine health ---> place probe PRE turbo
Turbo health ---> place probe POST turbo.

If you can only afford one - place it pre turbo because you can still use the gauge to determine when to shut down the engine. Just remember that if the engine has been under a heavy load, the engine should sit at your cool down temp for longer. In other words; Pre placement gives accurate engine temp readings and fairly accurate turbo temp readings. Post placement give very accurate turbo temp readings and unusable (inaccurate) engine temp readings.