One array ‘front’ and one array ‘rear’ suggest, like myself, that they face 180 degrees apart, yet your peak production is only 2 hours apart. Assuming Australia, around solar noon, you appear to have both arrays facing South to West.
Configuration settings must be accurate. Location, elevation from horizontal, array peak generation, and azimuth (which is measured differently in Forecast Solar) are critical. Then the inverter capacity figure limits the solar forecast should this exceed the maximum the inverter can deal with.
After that, it is a forecast. Based on clear sky estimates for your location / array orientation, but reduced for weather and atmospheric conditions. On a clear sky sunny day, with the correct settings, the actual should match the forecast. Issues with alignment have been noted.
Weather accuracy is another subject. Note that the integration uses an EU based estimate / forecast, which may not be as appropriate when in the Southern Hemisphere.
In my experience, ratio of actual production to day forecast can vary from around 0.5 to 2, and for myself averaging at around 1.3 over time as my array is shaded early & late.
Hourly forecast figures can be very inaccurate. I continue to collect daily solar and weather forecast and actuals in the hope that I might find a model that can be used to better estimate day and hour ahead values.
this should fit your needs better than forecast.solar:
