Guva-S12SD sensor right-angle window mounting ?

A detailed review of the Guva-S12SD sensor by blogger Wolfgang Ewald stated that one shouldn’t work with an angle of incidence of 90°, and that it should be sensibly positioned towards the sun. Which got me thinking of a motorised option to achieve this automatically.

I am only looking to record whole number results, nothing too accurate, and as the sun comes past my window during the afternoon hours of the day (which is the period of time that I need), would I not get away with the sensor permanently mounted at an angle upward at the sky, as these would be the main hours to be weary of UV radiation ?

ref : https://wolles-elektronikkiste.de/en/uv-sensors-and-sensor-modules