Hi,
I have clicked to the question mark to Irradiance Optimization and pop up GCR as you can see screenshoot.
On the other hand, André, according to your explanation in this forum, I interpretate that Irradiance Optimization refers to have Tracker Gain in case we have cloudy days (diffuse irradiance). Am I correct? if I am, this option can be selected only if the tracker manufacturer offers this technology to the PV system.